genetic resources, agro-techniques, value addition and

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ICAR-CTCRI

ICAR – Central Tuber Crops Research Ins�tuteSreekariyam, Thiruvananthapuram – 695 017, Kerala

Genetic Resources, Agro-Techniques,Value Addition and Utilisation in

Tropical Tuber Crops: Current Prospects for North Eastern States in India

P. Murugesan I K. Laxminarayana I Visalakshi Chandra C.

Namrata A. Giri I Suresh Kumar J. I Sanket J. More I P. Sethuraman Sivakumar

Technical Bulletin No: 80

ICAR – Central Tuber Crops Research Ins�tuteSreekariyam, Thiruvananthapuram – 695 017, Kerala

Genetic Resources, Agro-Techniques,Value Addition and Utilisation in

Tropical Tuber Crops: Current Prospects for North Eastern States in India

Published by

Dr. V. Ravi

Director (A)

ICAR-Central Tuber Crops Research Institute

Sreekariyam, Thiruvananthapuram – 695 017, Kerala, India

Tel. No.: (91) (471) 2598551 to 2598554; Fax: (91) (471) 2590063

E-mail: [email protected]; Website: http://www.ctcri.or

Compiled & Edited by

Dr. P. Murugesan

Dr. K. Laxminarayana

Dr. Visalakshi Chandra C.

Dr. Namrata A. Giri

Dr. Suresh Kumar Jabu

Dr. Sanket J. More Dr. P. Sethuraman Sivakumar

Photo Credits & Cover design: Dr. Sanket J. More

Citation: P. Murugesan, K. Laxminarayana, Visalakshi Chandra C., Namrata A. Giri, Suresh Kumar J.,

Sanket J. More and P. Sethuraman Sivakumar. 2020. Genetic Resources, Agro-techniques, Value Addition

and Utilisation in Tropical Tuber Crops: Current prospects for North Eastern States in India. Technical

Bulletin No. 80. ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala, 63 p.

February 2020

Copyright© 2020 ICAR-CTCRI. All rights reserved.

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ICAR-CTCRI

Design & Print

Aden Digital Signage, Thiruvananthapuram, India-695001, Mob:+91 9605206323

Genetic Resources, Agro-Techniques, Value Addition and Utilisation in Tropical Tuber Crops: Current Prospects for North Eastern States in India

Tropical Tuber crops such as cassava, sweet potato, yams, edible aroids, elephant foot yam, taro and tannia

are the major sources of dietary energy, feeding billions of people across the globe. The north eastern region

of India covering seven states such as Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland

and Tripura are one of the major hotspots of biodiversity known for enormous genetic diversity of tuber

crops. Considerable genetic diversity exists among the tropical tuber crops for plant type, morphological and

physiological characteristics, reactions to diseases and pests, adaptability and distribution. The tropical tuber

crops play a vital part in the diet of the tribal people. They are being cultivated mainly for food, poultry and

piggery feed and for therapeutic purposes, although in a primitive way. The industrial application of tuber

crops grown here is not well known. Imparting knowledge on the various aspects of tropical tuber crops

cultivation such as modern agro-techniques, propagation techniques, high yielding varieties, nutritional

value and value addition assumes significance. Hence, this technical bulletin entitled ‘Genetic resources,

agro-techniques, value addition and utilisation in tropical tuber crops: current prospects for North Eastern

states in India’ was prepared to provide required information for the benefit of tuber crop growers, processing

Industries and consumers. I hope that this bulletin would be useful to North East Scheme and helps in overall

improvement and wider utilization of the tropical tuber crops. I congratulate the authors who have

contributed to the technical bulletin.

20 February 2020 Dr. V. Ravi,

Thiruvananthapuram Director

FORWARD

Sl. No. Chapter Page No.

Tropical Tuber Crops Genetic Resources and Farmers Variety

Protection- Relevance to North Eastern States of India

Agro-techniques in Tropical Root and Tuber Crops in

Perspective to NEH Region

High Yielding Varieties of Tuber crops Suitable

for North Eastern Region

Planting Material Production Techniques in Tropical Tuber Crops

Rapid Multiplication of Quality Planting Material of

Tropical Tuber Crops through Minisett Technology

A Hidden Treasure - Sweet Potato

Nutritional Importance of Tropical Tuber Crops and

Opportunity of Processing in NE States

1 5

2 10

3 27

4 37

5 44

6 50

7 56

INDEX

Introduction

The North-Eastern (NE) region of India, covering nearly 2,62,379 sq km area, comprises eight states – Arunachal

Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura. This region has been categorized into

Eastern Himalayas, Northeast hills and the Brahmaputra and Barak Valley plains. It shares international border with

Bangladesh, Bhutan, China (Tibet), Myanmar and Nepal. The region is the 'gateway' for much of India's flora and fauna

with a high level of endemism, and as a result, it forms one of the richest vegetation types ranging from tropical rain

forest in the foothills to alpine meadows and cold deserts. The region is also the home of approximately 225 tribes, out

of 450 in the country. The economy of entire NE region is agriculture-based; though, little land is available for settled

agriculture. Agriculture has been the main livelihood amongst the tribal in both hills and plains. Along with the settled

agriculture, 'jhum' or shifting cultivation or 'slash and burn' method of cultivation is carried out by majority of tribal

groups, which contributes 85 per cent of the total cultivation in hilly tracts. In this system farmers change their fields to

uncultivated land after taking produce for 2-3 seasons, and this system sustains on the natural regeneration of soil

fertility. Out of 35 biodiversity hotpots identified in world1, this region forms a part of two hotspots – 'Himalayan'

Biodiversity Hotspot (Sikkim and Arunachal Pradesh) and 'Indo-Burma' Biodiversity Hotspot (remaining states). Out

of about 18,000 species of higher plants in India, the NE region alone holds about 7,000 plant species.

Tuber crops germplasm

NE region of India, a part of 'Himalayan' as well as 'Indo-Burma' Biodiversity Hotspots, is a treasure-trove of plant

genetic resources of food and agriculture importance. In case of tuber crops, Dioscorea has rich species diversity from

this region. In diosco The major species found in the region are D. alata, D. esculenta, D. bulbifera, D. pentaphylla, D.

hamiltonii, D. cylindrical, D. sativa, D. oppositifolia and D. deltoidea and D. floribundarea, both Dioscorea alata and D.

esculenta are grown locally and the tubers are also occurring in forests. Colocasia, Xanthosoma, Amorphophallus are

important tuber crops has vast potential. Most of the tuber crops are grown as mixed crop here. In case of colocasia

Mukhi and Panch mukhi are commonly grown in Assam and Garo hills of Meghalaya. Colocasia is believed to be

originated in Southeast Asia, probably Indo-Burma region. More than 200 landraces have been reported from this

region. Various groups of Alocasia are available in Assam.

Genetic resources of Tripura

Tripura being a part of North-East India and Indian Himalayan region belongs to one of the two “Hot Spot” of India

amongst 18 identified in the World. This region is unique; diverge in soil, climate and topography and rich in

horticultural biodiversity viz., fruits, vegetables, spices, medicinal plants and flowers particularly orchids. Farmers here

maintain high levels of crops diversity by rotation of crops in time and space together with adoption of both mono and

mixed cropping practices. In Tripura, 80% of people depend on agriculture for their food and daily livelihoods,

therefore known for diversity of genetic resources of crop plants, their wild relatives and has a rich repository of wild

plants of food values. The rich inter-specific diversity exists for genera like Oryza, Avena, Amaranthus,Chenopodium,

Fagopyrum, Allium, Hordeum, Linum,Saccarum, Citrus, Musa, Pyrus, Prunus, Rubus,Fragaria, Sorbus, Rosa,Lilium,

Vicia,Vigna, Lepidium, Lathyrus, Dioscorea, Orchids, Colocasia, Cucumis,Solanum, Trichosanthes, Bamboos and

Canescontributing significantly in the sustenance of the traditional Himalayan agro-ecosystems.

High genetic diversity for tuber and rhizomatouscrops viz., Ipomea batatus, Colocasia esculenta, Amorphophalous

TROPICAL TUBER CROPS GENETIC RESOURCES AND FARMERS VARIETY PROTECTION- RELEVANCE TO NORTH EASTERN STATES OF INDIA

Murugesan P. and Visalakshi Chandra C.ICAR-Central Tuber Crops Research Institute, Sreekariyam, Thiruvanathapuram, Kerala-695017

[email protected]

5Technical Bulle�n

bulbifera, Amorphophallus paeoniifolius, Amorphophallus campanulatus, Dioscorea alata, D. bulbifera, D.

oenitophylla, D. esculenta,D.pubera, D. arachnidaD.belophylla, D. trinervia, D.wattii, D. sativaD. kamoonensis, D.

pentaphylla, D.cylendrica,D. hamiltonii, D. oppositifolia and D. prazer iare found in Northeastern region. White

skinned and the red skinned varietiesof sweet potato are grown widely. A number of Dioscorea species alata, bulbifera,

brevipetiolata, esculenta, hamiltonii, hispida, kamaonensis, nummularia, pentaphylla, puber and quinata. D.

hamiltonii occurs in humid forests of NE hills.

Among the tuber crops, Colocasia is the major one. The region is rich in colocasia diversity both for wild and cultivated

types. Colocasia is an integral part of jhum cultivation and an important component in food chain of tribal farmers in

Northeast India. All the parts are edible and several traditional cuisines are being prepared out of it. The tubers are rich

in starch, minerals and energy. Although this region is rich in genetic diversity of colocasia, many landraces have

become extinct due to variety of factors. It is cultivated widely in this region as a mixed crop along with paddy in jhum

fields and as a mixed crop along with Xanthosoma, maize, leafy vegetables, chillies etc. in homestead gardens. It is

cultivated as mono crop in some of the isolated areas. Corms, cormels, leaves, petioles and flowers are edible. It is an

integral component in food chain and culture of many ethnic groups. They are preparing several traditional dishes from

different parts of the plant. It also occupies substantial share in pig and poultry feed in rural areas.

The tubers and leaves are rich in nutrients and they are having medicinal values too. Although the Northeast region of

India is rich in genetic diversity of colocasia, many landraces have become extinct due to variety of factors. So far, little

or no attention has been given for conservation of colocasia in this region. This has resulted into loss of several valuable

germplasm. Phytophthora leaf blight, corm borer, climate change, urbanization, decline in soil fertility, change in food

pattern, introduction of new crops and varieties etc are some of the factors that have threatened the existence of the

landraces of colocasia. Therefore, it is necessary to take urgent steps to collect and conserve these germplasm.

ICAR-CTCRI, the National repository of tuber crops germplasm made an effort to collect diverse genetic resources of

important tuber crops from Tripura with the help of ICAR-Research Complex for NEH, Tripura Centre. 36 germplasm

collections including cassava (1), sweet potato (6), yams(9), taro(16) and elephant foot yam(4) for conservation and

characterisation at CTCRI. The collection included farmer's varieties, local landraces and popular varieties of Tripura.

Variety Protection

In order to provide for the establishment of an effective system for the protection of plant varieties, the rights of farmers

and plant breeders and to encourage the development of new varieties of plants it has been considered necessary to

recognize and to protect the rights of the farmers in respect their contributions made at any time in conserving,

improving and making available plant genetic resources for the development of new plant varieties. he Government of

India enacted “The Protection of Plant Varieties and Farmers' Rights (PPV &FR) Act, 2001” adopting sui generis

system. Indian legislation is not only in conformity with International Union for the Protection of New Varieties of

Plants (UPOV), 1978, but also have sufficient provisions to protect the interests of public sector breeding institutions

and the farmers. The legislation recognizes the contributions of both commercial plant breeders and farmers in plant

breeding activity and also provides to implement TRIPs in a way that supports the specific socio-economic interests of

all the stakeholders including private, public sectors and research institutions, as well as resource-constrained farmers.

To implement the provisions of the Act the Department of Agriculture and Cooperation, Ministry of Agriculture

established the Protection of Plant Varieties and Farmers' Rights Authority on 11th November, 2005.

Rights under the Act, gene bank and gene fund

Apart from breeders' rights provision is there for Researchers' Rights and farmers rights. Researcher can use any of the

registered variety under the Act for conducting experiment or research. This includes the use of a variety as an initial

source of variety for the purpose of developing another variety but repeated use needs prior permission of the registered


breeder. A Farmer who has evolved or developed a new variety is entitled for registration and protection in like manner

as a breeder of a variety; Farmers variety can also be registered as an extant variety; A farmer can save, use, sow, re-sow,

exchange, share or sell his farm produce including seed of a variety rotected under the PPV & FR Act, 2001 in the same

manner as he was entitled before the coming into force of this Act provided farmer shall not be entitled to sell branded

seed of a variety protected under the PPV&FR Act, 2001; Farmers are eligible for recognition and rewards for the

conservation of Plant Genetic Resources of land races and wild relatives of economic plants; There is also a provision

for compensation to the farmers for non-performance of variety under Section 39 (2) of the Act, 2001 and Farmer shall

not be liable to pay any fee in any proceeding before the Authority or Registrar or the Tribunal or the High Court under

the Act. Authority has established National Gene Bank to store the seed material including parental lines submitted by

the breeders of the registered varieties. The seed lot is stored under low temperature conditions at 5º C for the entire

registration period, and if necessary, after few years of storage in the National Gene Bank, the seed lot will be

rejuvenated and replenished at the cost of the applicant. The seed stored in the National Gene Bank will used for dispute

settlement or when an exigency arises for invoking compulsory licensing provision. Such a seed deposition in the

National Gene Bank would dissuade market malpractices or violations as the sample in custody can be drawn to verify

the facts. When the period of registration granted lapses, the material automatically moves to public domain. A National

Gene Fund has been established by the Authority to receive the contributions from: The benefit sharing received in the

prescribed manner from the breeder of a variety or an essentially derived variety registered under the Act, or the

propagating material of such variety or essentially derived variety, as the case may be; The annual fee payable to the

Authority by way of royalty; The compensation deposited by breeders and The contribution from any National and

International organizations and other sources. The Gene Fund shall be utilized for Any amount to be paid by way of

benefit sharing, The compensation payable to the farmers/community of farmer', The expenditure for supporting the

conservation and sustainable use of genetic resources including in-situ and ex-situ collections and for strengthening the

capability of the panchayat in carrying out such conservation and sustainable use, The expenditure of the schemes

relating to benefit sharing. Benefit sharing The benefit sharing is one of the most important ingredients of the farmers'

rights. Section 26 provides benefits sharing and the claims can be submitted by the citizen of India or firms or non-

governmental organization (NGOs) formed or established in India. Depending upon the extent and nature of the use of

genetic material of the claimant in the development of the variety along with commercial utility and demand in the

market of the variety breeder will deposit the amount in the Gene Fund. The amount deposited will be paid to the

claimant from National Gene Fund. The Authority also publishes the contents of the certificate in the PVJI for the

purpose of inviting claims for benefits sharing.

Rights of Community

It is compensation to village or local communities for their significant contribution in the evolution of variety which has

been registered under the Act. Any person/group of persons/governmental or non-governmental organization, on

behalf of any village/local community in India, can file in any notified centre, claim for contribution in the evolution of

any variety. A balanced approach towards protecting the interests of the plant breeders and the traditional farming

communities was needed It emphasizes farmers' Rights as positive rights capturing the spirit of FAO international

treaty on plant genetic resources and UN convention on biological diversity. The major objectives of the Act include

providing an effective system for protection of plant varieties and rights of farmers and plant breeders, recognizing and

protecting the rights of farmers in respect of their contribution made at any time in conserving, improving and making

available plant genetic resources for the development of new plant varieties, contributing to accelerate the agricultural

development in the country, stimulate investment for research and development in public / private sector for

development of plant variety; and facilitating the growth of seed industry.


Farmers' Rights and Community Rights

A farmer as the provision in the Act if bred or developed a new variety shall be entitled for registration in the like manner

as a plant breeder. The farmer is also entitled to save, use, sow, re-sow, exchange, share or sell his farm produce

including seed of a registered variety under the Act like wise entitled before the enforcement of the Act. Farmers are not

entitled to sell branded seed of the variety registered under the Act. 3. Farmers' Variety is the variety which has been

traditionally cultivated and evolved by the farmers in their fields or is a wild relative or land race of a variety about

which the farmers possess the common knowledge.

Plant Genome Saviour Community Awards

PPV&FR Authority has constituted plant genome saviour awards to farmers viz; community award and individual

farmers reward and recognition. To recognize farmers contribution PPVFR Authority confers annually Plant Genome

Savior Community Awards from the National Gene Fund. The award consists of Rs. 10 lakhs in cash along with citation

and memento. A maximum of 5 such awards are conferred every year to communities/tribal communities. The selection

of awardees is done by a high-level national committee. The Award is open to all Indian farming communities,

particularly the tribal and rural communities engaged in conservation, improvement and preservation of plant genetic

resources of economic plants and their wild relatives particularly in the areas identified as agro-biodiversity hotspots.

The applicants are required to submit evidences in support of the conservation work done by them, provide

seeds/planting material of the conservation varieties, brief proposal for the utilization of the award money in

community welfare and also to inform if the material has been utilized by any breeders in developing any other

improved varieties etc. Similarly, under Section 39 of PPV&FR Act, 2001 confers confers Plant Genome Saviour

farmers reward and recognitions. In reward and recognition maximum ten farmers are rewarded which comprises of

citation, memento and cash of Rs. 1 lakh each.

Registration of Plant Varieties of Farmers

The PPV&FR Authority follows a broad principle of internationally recognized system of Distinctiveness, Uniformity

and Stability (DUS) and Novelty for a new variety. Any person can apply for registration of any of the following

categories of varieties:� New Variety: A new variety should conform to the criteria of novelty [not been sold or

otherwise disposed of in India, earlier than 1 year and outside India (in case of trees and vines earlier than six years, or, in

any other case, earlier than four years), distinctiveness (for at least one essential character from all varieties of common

knowledge), uniformity (sufficiently uniform in its essential characteristics) and stability (if its essential characteristics

remain unchanged after repeated propagation, or, in the case of a particular cycle of propagation, at the end of each

cycle).

Extant Variety means a variety available in India which is Notified under section 5 of Seeds Act, 1966, about which

there is a common knowledge; in public domain, farmers' variety that has been traditional by cultivated and evolved

by farmers in their fields, is a wild relative or landrace about which farmers possess common knowledge. Essentially

Derived Variety: In respect of the initial variety, shall be said to be essentially derived from such initial variety when it :

o is predominantly derived from the initial variety, or from a variety that itself is predominantly derived from initial

variety, while retaining the expression of the essential characteristics that results from the genotype or combination of

genotypes of initial variety; o is clearly distinguishable from such initial variety; and o conforms (except for the

differences which result from the act of derivation) to such initial variety in the expression of the essential

characteristics that result from the genotype or combination of genotype of such initial variety. Authority has developed

crop specific "Guidelines for the Conduct of Test for Distinctiveness, Uniformity and Stability' which provide detailed

practical guidance for the harmonized examination of DUS of the candidate variety and, in particular, to identify

appropriate characteristics for the examination of DUS.


Greater Yam genetic diversity in Tripura

Elephant foot yam genetic diversity in Tripura

Taro genetic diversity in Tripura

Local Sweet Potato varieties


Introduction

The cassava was probably domesticated in South America but possibly in Mexico, and sweet potato probably in

Mexico but possibly in South America, some 8,000 years ago. These crops have wild relatives in both Central and South

America. Much later, after Columbus discovered the New World in 1492, European sailors introduced the potato to

Europe and from there to many other parts of the world, and both cassava and sweet potato to Africa and then Asia.

Interestingly, the sweet potato was being grown in Oceania before Columbus, but the routes of introduction are still

debated. Cassava is the most important root and tuber crop in the tropics where it is a primary staple food in many of the

poorest countries, with the largest production in Nigeria, Brazil, Thailand, and Indonesia. The sweet potato is also a

food staple in Asia, Africa, and America, but with production dominated by China, where half of the crop goes for

animal feed. Yams are also important staple food crops in tropical and subtropical regions. The four main cultivated

yams were independently domesticated on three continents some 7,000 years ago: Dioscorea rotundata and D.

cayenensis in West Africa, D. alata in Southeast Asia and the South Pacific, and D. trifida in South America. Today,

however, the major producers are in West Africa: Nigeria, Ivory Coast, Ghana, and Benin.

The edible storage organs are underground tubers for yams, storage roots for cassava and sweet potato, and

corms/cormels for taro and cocoyam. All of these organs store energy as starch and the crops are viewed primarily as

sources of carbohydrate energy when used as a food staple. They are, however, also valuable sources of minerals,

vitamins, and other antioxidants. In addition, there is a trend toward using them to produce processed products for both

human consumption and industrial use. All of the crops are vegetatively propagated: yams and aroids through their

tubers, cassava as stem cuttings, sweet potato as vine cuttings, and taro and cocoyam through side shoots, stolons, or

corm heads.

Root and tuber crops are the third important food crops after cereals and grain legumes, and constitute either staple or thsubsidiary food for about 1/5 of world population. Tuber crops offer good scope for income generation, livelihood and

nutritional security to the downtrodden people. Tropical root and tuber crops had higher biological efficiency and

highest rate of dry matter production due to most efficient converters of solar energy. They supply cheaper source of

energy to the weaker sections of the society and also provide minerals and vitamins. Besides contributing to food and

nutritional security, tuber crops also create employment opportunities for millions of people.

Cassavath

Cassava (Manihot esculenta Crantz) or tapioca belongs to the family Euphorbiaceae is the 6 most important crop (after

wheat, rice, maize, potato and barley) in the world and it is the major among the tropical root and tuber crops (Pujole et

al., 2002; Meireles da Silva et al., 2003). Cassava is the most important carbohydrate source for human consumption as

well as livestock feed and has a variety of industrial uses including processed food, textiles, pharmaceuticals,

flavouring agents such as monosodium glutamate and is a source of energy in the diet of most tropical countries of the

world. Cassava is the most important sources of energy in the diet of most tropical countries of the world. Major cassava

producing countries in the world are Nigeria, Thailand, Indonesia, Brazil, Angola, Ghana, Mozambique, Viet Nam,

Cambodia and India. Currently cassava is a fundamental component in the diet of millions of people. Globally it -1

occupies an area of 24.59 m ha with a production of 277.81 mt and productivity of 11.30 t ha (FAO, 2018). Africa

contribute highest area (18.68 m ha) with a production of 169.67 mt, whereas Asian countries occupy an area of 3.75 m -1

ha, production of 80.64 mt and productivity of 21.48 t ha . Among the cassava growing countries, Nigeria stands first in -1

area (6.85 m ha) and production (59.48 mt) with an average productivity of 8.68 t ha , whereas it is being grown in an -1

area of 0.228 m ha in India with a production of 4.65 mt and a productivity of 20.40 t ha . In fact, worldwide

K. LaxminarayanaRegional Centre, ICAR - Central Tuber Crops Research Institute,

Dumuduma Housing Board, Bhubaneswar-751019, Odisha, India

AGRO-TECHNIQUES IN TROPICAL ROOT AND TUBER CROPS

IN PERSPECTIVE TO NEH REGION


productivity increased by about 18.4% in the last 10 years (Ceballos, 2010). In India, tapioca is the most important tuber

crop cultivated in Tamil Nadu (1.21 lakh ha) followed by Kerala (0.71 lakh ha), Andhra Pradesh (0.18 lakh ha),

Nagaland (0.062 lakh ha) and Meghalaya (0.053 lakh ha).However, its production was highest in Tamil Nadu (4.98 mt)

followed by Kerala (2.58 mt) and Andhra Pradesh (0.37 mt). It is being considered as staple food crop in Kerala as well

as the tribal and north eastern hilly regions and as an industrial crop in Tamil Nadu, Andhra Pradesh and Maharashtra. In

North Eastern Hilly region, it is being extensively cultivated in the jhum areas of Garo Hills districts of Meghalaya,

some parts of Nagaland, Manipur, Tripura, Arunachal Pradesh and Mizoram. It is consumed both as freshly cooked

tubers and component of animals and poultry feeds too. Industries make use of tapioca for producing starch and

glucose.

Climate and Soil: It grows better in warm and humid climate with well distributed rainfall. It can tolerate to drought,

once it is established. In tropical and sub tropical regions cassava has the ability to tolerate extreme temperatures by

defoliation of leaves.

Tapioca grows on all types of soils, but saline, alkaline, and ill-drained soils are not suitable. Good fertile lands are

better for higher productivity. It can also be grown in marginally degraded wastelands with poor soil fertility.

Sl. No. CultivarDuration (Months)

Yield -1(t ha ) Special features

H-97 10 25-35 Semi branching, starch content 30%.

H-165 8 33-38 Non-branching, early maturing type, starch content 24%.

H-226 10 30-25Semi branching, starch content 29%, susceptible to cassava mosaic disease (CMD).

Sree Sahya 11 35-40 Semi branching, starch content 30%.

Sree Vishakam 10 35-38 Semi branching, yellow flesh with carotene, starch content 26%.

Sree Prakash 7 30-35Semi branching, starch content 30%, early maturing, suitable for lowlands as a rotation crop.

Sree Harsha 10 35-40Erect branching, early maturing, excellent cooking quality, usceptible to CMD, starch content 38-41%.

Sree Jaya 7 26-30Erect branching, early maturing, excellent cookingquality, suitable for lowland as a rotation crop, susceptible to CMD

Sree Vijaya 7 30-35Erect branching, early maturing, susceptible to spider mites and scale insects, suitable for low land as a rotation crop.

M4 10 18-23 Non-branching, good table variety, susceptible to mites.

Sree Rekha 10

10

10

10

10

35-40Erect branching, good table variety, suitable forboth upland and lowland conditions.

Sree Prabha 35-40Semi-branching, good table variety, suitable for both up lands and low land conditions.

Sree Padmanabha 29-30 Resistant to cassava, mosaic disease with normal yield.

Sree Athulya 35-40Variety with stable and high extractable starchcontent (30.2%), higher yield, ideal for cultivation in industrial areas of Tamil Nadu.

Sree Apoorva 35-40Variety with stable and high extractable starch content (30.1%) and higher yield, ideal for cultivation in industrial areas of Tamil Nadu.

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1

Improved varieties


Planting season: Plant the setts in April - May (main season) before onset of South West monsoon or

September - October coinciding with the North-East monsoon. It can be planted at any time of the year, if it

was grown as an irrigated crop. As the South West monsoon arrives early in NEH region, tapioca can be

planted in second fortnight of March to April after preparation of jhum lands for cultivation.

Methods of planting

Mound method: This method will be followed in poorly drained soils. In general planting of the cassava setts

will be done by preparation of the mounds at a height of 25-30 cm. It is the most suitable method of planting in

sloppy areas in jhum lands of NEH region.

Ridge method: This method will be followed in sloppy lands for rainfed crop and in plains for irrigated crop

by preparing the ridges across the slope/along the contour to a height of 25-30cm in order to control the soil

erosion and water runoff.

Flat method: Flat bed method of planting will be followed in uniformly levelled lands having good drainage.

Ideal planting material: Select planting materials from mature, healthy stems having 2-3 cm diameter.

Discard the woody basal portion and tender top portion of the stem for planting. Prepare the setts of 15-20 cm

length with a smooth circular cut. Setts prepared from the stems stored for 1-2 months with leaves intact will

give better sprouting.

Sett planting: Plant the setts vertically to 10.0 cm depth (⅔ portion of the setts below the surface and ⅓

portion of the setts above the ground) at a spacing of 90cm x 90cm for branching/ semi branching types and 75

cm x 75cm for non branching varieties. The setts may be planted very close so as to accommodate 400 setts 2

per m area. Irrigate the nursery in case of prolonged dry spells. Rogue out the plants showing mosaic

infestation and replaced by symptom-free settlings for planting at three weeks stage in the main field. Irrigate

the crop in the absence of rain and long dry spells to realize good yields.-1 Manures and Fertilizers: Incorporate 12.5 t ha of well decomposed farmyard manure at one month in

advance of planting. In-situ incorporation of green manures or green leaf manures is beneficial to enhance the -1 crop productivity and to sustain the soil quality. A fertilizer dose of 100-50-100 kg N, P O and K O ha is 2 5 2

recommended.

Fertilizer recommendation

Urea

Mussorie rock phosphate

Muriate of Potash (M.O.P.)

Single Super Phosphate (S.S.P.)

M.O.P.

1

2

3

1

2

3

Or

Urea

S. No.

100

250

85

100

300

85

110

85

100

85

Or

Urea

Di-Ammonium Phosphate (D.A.P.)

1

2

65

110

110

Fertilizer -1Basal dressing (kg ha )-1Top dressing (kg ha )

45-60 days after planting


M.O.P.

Or

Urea

3

1

Ammonium phosphate/ Factomphos (20:20)

M.O.P.

2

3

85

250

85

85

110

85

Entire dose of P fertilizers needs to be applied at before planting, whereas split doses of N and K fertilizers is beneficial

to enhance the nutrient use efficiency and to minimize the losses of costly fertilizer inputs. In case the soils contain

higher levels of available P, its application can be skipped for 2-3 years and thereafter, a maintenance dose of 50% needs

to be applied. Retain only two healthy shoots on opposite sides and remove rest of the sprouts at 30-45 days after

planting. Maintain the field with weeds free, top dress with fertilizers and then earth up the crop. A second weeding and

earthing up may be given 1-2 months after the first weeding and earthing up.

Crop Protection: Cassava is affected by a few serious pests and diseases. Spider mites occur during dry season from

January to May, feed on leaf sap, causing blotching, curling and leaf shedding. Spraying of Dimethoate or

Chloropyriphos @ 0.05% at monthly interval starting from January to control the mites infestation to the crop. Spraying

water on the foliage at 10 days interval is also effective. Scale insects infest the stems when stacked and occasionally in

the field, causing drying of the stems. Collect the stems free of scale insects and store them in vertical position under

shade to prevent multiplication of scale insects. As prophylactic measure, spray the stems with 0.05% dimethoate

during storage.

Cassava mosaic disease: Cassava mosaic disease is caused by Indian cassava mosaic gemini virus. Chlorotic areas

inter mixing with normal green tissue gives mosaic pattern. In severe cases leaves are reduced in size, twisted and

distorted, reducing chlorophyll content and photosynthetic area. It causes 25-80% yield reduction. Use disease-free

planting material as prophylactic measure. Grow CMD tolerant varieties like H-97, H-165, Sree Visakham, Sree Sahya

and Sree Padmanabha. Rouge-out infected plants and follow strict field sanitation. Keep the fields free of self sown

cassava plants which may serve as a source of inoculum and help the spread of disease. Prompt disposal of cassava

residues from the infected fields is very essential.

Tuber root: Tuber root is caused by Phytophthora palmivora. Infected tubers show brown discoloration of internal

tissues, rotten and emit foul smell and unfit for consumption or marketing, causing heavy yield loss.

Mealy bug: It feeds on the sap of plants and injects a toxic substance into its host, resulting chlorosis, stunting of the

plants, leaf deformation and early leaf drop. Add 20ml of neem oil and 2-5 ml of soap solution in a litre of water, shake

the solution vigorously till it looks milky white with foam. Dip the setts of cassava for 5minutes in this solution, so

larval stages of mealy bugs will be washed off and killed. Spray the same solution in mealy bug infested cassava field

also. Nozzle of the spray should be turned towards the lower side of the leaf and ensure full coverage by the spray fluid.

A second spray after 15days may ensure the death of residual population is recommended for the control of mealy bugs.

There are number of natural enemies in the field to check the population of mealy bugs, but the indiscriminate use of

chemical insecticides will adversely affect its natural enemies and pave the way for pest resurgence. Insecticides like -1 -1 -1

Profenophos 50 EC @ 2 ml l ; Chloropyriphos 20 EC @ 4 ml l ; Dimethoate 30 EC @ 2 ml l are reported to be effective

against mealy bugs.

Other management practices like ploughing the land to 20-25" depth using disc plough, adoption of ridge method of

planting, crop rotation with cereals, sugarcane and turmeric once in two years, provision of drainage, removal of

infected tubers from field and incorporation of Trichoderma viridae in the soil destroy them.

Intercropping: Select only bushy type of intercrops like Cowpea, Groundnut, French bean which mature within 100

days. Plant tapioca in the month of May-June at a spacing of 90 x 90cm and dibble the intercrop seeds immediately after


planting of tapioca. Apply the recommended dose of NPK fertilizers to the intercrops about 30 days after sowing

followed by inter culturing. Top dress tapioca immediately after harvest of intercrops with the recommended dose of -1

NPK fertilizers and earth up. Inter crops in tapioca gives an additional net income of Rs. 3000 – 5000 ha within 3 - 3½

months by utilizing light, water and nutrients more effectively from the interspaces of tapioca. The inter crops could

able to control weeds and adds organic matter and nitrogen to the soil.

Harvesting: Harvest the crop depending upon the maturity of the cultivar from 7-10 months after planting. Stack the -1

stems vertically in well aerated shady places for subsequent planting. Its yield varies from 30-60 t ha based on the

cultivars, native soil fertility and its good agronomic practices. Harvest the required quantity of tubers as per the local

demand and care should be taken not to store the harvested tubers more than 2-3 days to avoid post physiological

deterioration.

Sweet Potato

Sweet potato (Ipomoea batatas Lam.) belongs to the family convolvulaceae is an important tuberous root crop having

tremendous potential for utilization in food, feed and industrial sectors, especially for the production of starch, flour,

glucose and alcohol. They are good sources of vitamin C, B , B , B and E as well as dietary fibre, K, Cu, Mn and Fe. The 3 5 9

high nutrient content coupled with its anti- carcinogenic and cardio-vascular disease preventing properties resulted in

recognizing the crop as a healthy food. They are widely grown in the tropics and warm temperate regions of the world. -1Globally it grows in an area of 8.06 m ha with a production of 91.95 mt and productivity of 11.40 t ha in which China

contributes 30% area and 58% production (FAO, 2018). Africa contributes 57% area under sweet potato with 28% of

production. The major sweet potato producing countries in the world are China (53.25 mt), Nigeria (4.03 mt), Ethiopea

(1.83 mt), Indonesia (1.81 mt), Uganda (1.53 mt), India (1.40 mt), Viet Nam (1.37 mt), USA (1.24 mt), Madagascar -1

(1.09 mt) and Rwanda (1.08 mt). Highest productivity (t ha ) was recorded by Australia (36.42) followed by Egypt

(33.57), Spain (25.37), Cyprus (25.23), Palestine (24.90), China (22.38), Japan (22.31), USA (21.25), Mexico (20.24),

Italy (19.79), Israel (18.80), Jamaica (18.10), Peru (17.92), Malaysia (16.98), Indonesia (16.57), Fizi (14.99), Brazil

(14.52), Mozambique (12.96), Viet Nam (11.66) and India (11.45). In developing countries, it is ranked fifth in

economic value, sixth in dry matter production, seventh in energy production and ninth in protein production

(Lobenstein, 2009). In India, it is the third most important tuber crop after potato and cassava.

Globally, India occupies twelfth, tenth and eleventh rank in area, production and productivity respectively during 2013. -1In India, sweet potato occupies an area of 0.122 m ha with a production of 1.40 mt and productivity of 11.45 t ha ,

according to the estimates of 2017-18 (FAO, 2018). It is cultivated predominantly as a rain-fed crop in Eastern India,

especially in Odisha, West Bengal, Uttar Pradesh, Bihar and Jharkhand, accounting to 77% of area and 82% of

production (Edison et al., 2009). In India, Odisha ranks first in area (0.43 lakh ha) followed by West Bengal (0.23 lakh

ha), Uttar Pradesh (0.19 lakh ha) and Assam (0.096 lakh ha), while the production was highest in Odisha (0.41 mt)

followed by Uttar Pradesh (0.265 mt), West Bengal (0.236 mt) and Assam (0.041 mt). Sweet potato can be grown in a

wide soil and climatic regimes (Jansson and Ramon, 1991).

Climate and Soil: It is a crop of tropical and sub-tropical region having wide adaptability. It performs better in well

drained loamy soils. According to Bouwkamp (1985), sweet potato can be grown on a wide range of soil types but sandy

or sandy loam soils having good porosity and aeration with reasonably high organic matter content and permeable sub

soil are ideal. Some prominent genotypes of sweet potato are tolerant to moderate salinity in eastern India

(Laxminarayana et al., 2010; Laxminarayana, 2013; Laxminarayana and Burman, 2014). They are sensitive to alkaline

conditions. Adequate drainage is essential for their good growth. Heavy clays or soils rich in humus generally result in

good growth of shoots and leaves but normally result in low yields and poor quality tubers. Sweet potato is an acid

tolerant crop and yields are usually high in soils with a pH of 5.5 to 6.5. Agricultural lime should be applied @ 0.5 - 2.0 t -1

ha to the soils with pH below 5.5 to effectively raise the pH to acceptable levels. In USA, application of lime was found

to increase tuber yields in acid soils and Watts and Cooper (1943) detected maximum yields at a pH range of 6.5-7.5 in


Improved varieties

Sl. No. Cultivar Duration (Days)

Yield -1(t ha )

Special features

Varsha (H-268) 120-125 18-22Semi spreading, reddish purple skin, light yellow flesh,

good cooking quality.

Sree Nandini 100-105 20-25Spreading, skin is light cream, white flesh, good culinary

quality.

Sree Vardhini 100-105 20-25

Kanjangad 100-120 15-20

Sree Rethna 90-105 20-26

Sree Bhadra 90-95 20-27

Sree Arun 90-100 20-28

Sree Varun 90-100 20-28

Sree Kanaka 75-85 12-15

Gouri 75-85 19

Sankar 110-120

105-110

105-110

110-120

105-110

14

Kalinga 26-29

Goutam 18-32

Kishan 16-26

Sourin 16-32

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1

Semi-spreading, purple skin, light yellow flesh, good cooking

quality.

Semi-spreading, reddish purple skin, light yellow flesh,

good cooking quality.

Spreading, purple skin, orange flesh, excellent cooking

quality.

Semi-spreading, light pink skin, cream flesh, excellent

cooking quality, resistant trap crop for root-knot nematode.

Spreading, pink skin, cream flesh, good cooking quality.

Spreading, cream skin & flesh, good cooking quality.

-1Short duration hybrid, rich in carotene (8.8 - 10 mg 100 g

fresh weight).

Medium duration variety suitable for Odisha state.

Excellent cooking quality, suitable for Orissa

Open pollinated selection, suitable for cultivation in Orissa

Clonal selection, suitable for cultivate in Orissa

Clonal selection, medium duration, suitable for upland and

hilly areas

Clonal selection suitable for kharif and rabi seasons.

Nursery: Use vines or tubers depending upon the availability for raising nursery. Since huge planting materials (83,333

vine cuttings per ha) are required for cultivation of sweet potato, raise the nursery in two stages - Primary nursery and

Secondary nursery.

Primary Nursery: Raise nursery 3 months ahead of planting of the crop in the main field. A primary nursery area of 100 2m is required to raise the vines for planting one ha. Make ridges 60 cm apart and plant healthy tubers (125-150 g) or vine

cuttings on the ridges at a spacing of 20 cm. Apply good amount of organic manure before planting and 1.5 kg urea at 15

days after planting. Irrigate the nursery as and when required. Clip off the vines to a length of 20-30 cm at 45 days after

planting and the same vines will be used for secondary nursery.

silty loam and 6.0-7.0 in fine sandy loam soils ( Bouwkamp,1985).

Planting season: Under rainfed condition, plant the vines in June – July. Under irrigated conditions, plant the vines

during November - December in uplands and during January - February in lowlands as a summer crop.


2 2Secondary Nursery: Prepare nursery bed in an area of 500 m to plant vines obtained from 100 m primary nursery plot.

Apply well decomposed organic manure (FYM) in the last plough. Prepare the ridges at 60 cm apart. Plant the vine

cutting at 20 cm apart on the ridges. Top-dress the nursery with 5 kg urea in two split doses at 15 and 30 days after

planting. After 45 days, clip off the vine cuttings having 20-30 cm length and plant the vine cuttings in the main field.

Cuttings obtained from the apical portion of the vine are preferable for planting in the main field. Store the cut vines of

sweet potato with intact leaves in bundles under shade for two days prior to planting in the main field.

Field preparation and planting: Make ridges at 60 cm apart having 25-30 cm height. Plant the vine cuttings at 20 cm

spacing on the ridges. Plant the vines horizontally with three to four nodes (⅔ portion of vine cutting) below the soil

leaving the remaining portion (⅓) above the soil. Plant the vine cuttings in the soil at field capacity moisture level,

otherwise slight irrigation is required after planting of the vines. -1Manures and Fertilizers: Apply farm yard manure @ 5-10 t ha before preparation of the ridges one month ahead of

-1planting of vine cuttings. A general recommended dose of fertilizers i.e. 50-25-50 kg ha of N, P O and K O needs to be 2 5 2-1 -1

applied. Apply ⅓ of N (36 kg ha urea) and ½ K (42 kg ha of Muriate of Potash) at the time of planting, ⅓ N at 30 days

after planting and the left over ⅓ N and ½ K at 45-50 days after planting along the side of the ridges. Entire dose of P

fertilizers needs to be applied before planting. Integrated application of lime, FYM, NPK and MgSO in an acid Alfisol 4-1

of eastern India has recorded significantly highest mean tuber yield (13.69 t ha ) of sweet potato over the other

treatment combinations (Laxminarayana et al., 2015). Application of 50, 100 and 150% of the recommended doses of

NPK significantly increased the mean tuber yield of sweet potato by 44, 106 and 130 per cent over control. Half of the

recommended doses of NPK in combination with organic manures showed a yield response of 25, 12 and 32 per cent

over that of ½ NPK in respect of FYM, neem cake and green manure, however, addition of lime along with organic

manures and sub optimal doses of NPK showed an increase of 6, 13 and 19 per cent tuber yield in comparison to

organics + ½ NPK without lime (Laxminarayana et al., 2015). Fungal inoculation with VAM (Glomus microcarpum) @ -15 kg ha enhanced the root length density, volume with root hairs and VAM colonization releases organic acids

facilitates mineralization of organic P and solubilization of insoluble inorganic P fractions which ultimately contributed

higher absorption of P including Fe, Cu, Mn & Zn (O′Keefe and Sylvia, 1993).

Crop protection

Sweet potato weevil (Cylas formicarious): Sweet potato weevil is the most important pest causing very severe damage

to the crop. Adult weevil makes puncturing on vines and tubers. The grubs bore and feed inside the tubers by making

tunnels. Even the slightly damaged tubers are unsuitable for consumption due to bitterness. Yield loss may go up to

100% in severe cases. On an average, 20-50% tuber loss occurs due to infestation by sweet potato weevil. The following

integrated pest management will be effective for the control. Dip the vine cuttings in Fenthion or fenitrothion or -1 -1

Chloropyriphos solution @ 2.0 ml L or Imidacloprid @ 0.5 ml L for 30 minutes before planting. Install synthetic sex 2

pheromone traps @ 1 trap per 100 m area to collect and kill the male weevils. Destroy the crop residues after harvest by

burning as the harvested crop residues harbour the weevils.

Sweet Potato Feathery Mottle Virus (SPFMV): Among the 12 virus symptoms recorded, feathery mottle virus

(SPFMV) is widely occurred. The primary spread is through planting materials. The disease causes up to 50% crop loss.

The disease can be managed through cultivation of field tolerant varieties viz. Sree Vardini, use of virus free planting

materials as well as meristem derived plants.

Harvesting: Sweet potato matures around 110-120 days after planting. However, some of the early maturing varieties

like Kanjangad ready for harvest at 100 days after planting. Maturity of tubers can be determined by cutting fresh tuber

i.e. if the tuber is fully matured, the cut surface become dry otherwise it turns dark. Remove the vines and dig out the -1

tubers without any injury/ damage to the tubers. In general the tuber yield ranged from 10-30 t ha ; however it has the -1potential to yield 50-100 t ha . The tuber yield will increase if the crop remains in the field for longer period but the

tubers become hard and bitter due to sweet potato weevil infestation or rotting and it is advisable to remove at maturity.

Yams


Yam (Dioscorea spp) is third important tropical tuber crop after cassava and sweet potato. It is a perennial climber with

tuberous roots. The plants are formed from their underground rhizomes, where the vines are born, and of these leaves,

roots, and stolons of the plant. Plants produce tubers and bulblets (aerial tubers), which arise from the leaf axils. These

tubers are cylindrical and rich in carbohydrates, which allow the plant to survive under very dry climates. Yam tubers

can be large and reach 5-10 kg. the flesh may be white, yellow or purple depending on the variety grown. The leaves of

the plant are typically large, heart shaped and bright green. Sometimes they may have purple hues in leaves due to their

anthocyanin content. Yam is a dioecious plant, having female flowers (most abundant) and male flowers on the same

plant. They bloom at irregular times, which make the process of pollination difficult and cause low production of fruits

and seeds in this crop, which is only used for the production of tubers.

Nigeria is by far the world's largest producer of yams, accounting for over 70-76% of the world production. According

to the estimates during 2017-18, yams are being cultivated in an area of 8.69 m ha in the world with a production of -1

72.58 mt and productivity of 8.35 t ha (FAO, 2018). Around 98% area and 97% total production of yams contributed by -1African countries with a low productivity of 8.29 t ha . However, Asian countries have recorded highest productivity of

-118.34 t ha . Major yam producing countries in the world are Nigeria, Ghana, Benin, Togo, Congo, Colombia and

Ethiopia. Nigeria is the major producer of yams in an area of 2.90 m ha, production of 38.0 mt and productivity of 13.10 -1 -1t ha followed by Ghana with an area of 0.43 m ha, production of 6.64 mt and productivity of 15.44 t ha . According to

the International Institute of Tropical Agriculture, Nigeria accounted for about 66 percent of the yam production in -

Africa from 60% area. In India it occupies an area of 3,000 ha with a production of 80,000 t and productivity of 26.7 t ha1. Yams are tropical tuber crops which prefer long moist growing season. In India, they are cultivated largely in southern

and north eastern states. There are four main species of Yams grown in India viz., Greater yam - Dioscorea alata; Lesser

yam - D. esculenta; White yam - D. rotundata and Aerial yam - D. bulbifera. Greater yam and lesser yam are quite

popular since ancient items, white yam is a recent introduction from Africa. Yams are normally consumed as vegetable,

either boiled, baked of fried.

Climate and Soil: Yams grow well in warm and humid climatic conditions. Yam cannot withstand for frost. Yams

require well drained fertile soils and do not come up well with mean temperature of 30ºC and a well distributed annual

rainfall of 1200-2000 mm. March-May is the ideal time for planting.

Improved varieties

Sl. No. Cultivar Duration (Days)

Yield -1(t ha )

Special features

Sree Keerthi 9-10 25-30

Sree Roopa 9-10 25-30

Sree Shilpa 8 28

Sree Karthika 9 28-30

Orissa Elite 9 25-30

2

3

4

5

1

Tubers are conical in shape with brown skin and white flesh.

Starch content is 20-22%. Tubers have good cooking quality

and excellent taste.

Tubers are digitate in shape with black skin and white flesh

tubers have good cooking quality and taste. Starch content

17-19% and protein 1-2%.

Tubers are swollen, oval and smooth, skin black and white

flesh, cooking quality is good, starch content 17-19%.

High yielding selection with good cooking quality and shelf

life; suitable for Kerala state of India.

Suitable for rainfed irrigated conditions of Odisha, good

cooking quality.

Greater yam


Sree Kala 8-9 20-25

Sree Subhra 9-10 35-40

Sree Priya 9-10 35-40

Sree Dhanya 9 15-20

7

8

9

10

Lesser Yam

Tubers are oblong to fusiform in shape with greyish brown

skin covered with thin hairs and creamy white flesh. Tubers

have good cooking quality and flavour. Starch content is

118.4%.

Tubers are round and smooth with good cooking quality. The

cooked tuber is sweet to taste and without fiber.

Tubers are cylindrical in shape either brown partially hairy

skin and white flesh, starch is 21-23%. Possesses excellent

cooking quality.

Tubers have smooth surface with good cooking quality and

taste. Starch content 20-21% and protein 2-3%.

Dwarf type white yam which is bushy in appearance.

Stacking is not required. The height of the plant is about 30cm

and each plant forms a bush of about 50-60cm in diameter. It

has spineless stems and the starch content is 23.3%

Sree Latha 8-9 20-256

White yam

Good planting material: In case of greater yam and white yam, tuber pieces of 250-300g size can be used as planting

material for rapid seed yam production, whereas mini sets of 30g size is ideal. For planting lesser yam, medium sized

tuber of 100-150g is sufficient.

Land preparation: Plough/dig the land to a depth of 20-30 cm, then open the pits of 45x45x45cm size for planting of

greater yam and white yam at a spacing of 90x90cm. Fill up three-fourth (3/4) of the pit with top soil and FYM and

reform into a mound. For raising lesser yam, mounds may be formed at a spacing of 75x75cm after application of FYM.

Seed treatment: Prepare cow dung slurry by mixing fresh cow dung with sufficient water in a drum or container, add -1 -1 -1

Mancozeb @ 2-3 g kg seed material along with Chloropyriphos @ 1 ml L or Imidacloprid @ 0.5 ml L . The cut pieces

of yam were uniformly mixed with the cow dung slurry and kept for 4-5 hr. Then take out the yam pieces from the

container along with the cow dung slurry coating and dried under the sun light.

Method of planting: Plant seed tubers of greater yam/white yam on reformed mounds. About 3,000 – 3,700 kg of seed

material is required to cover one hectare. Plant whole tubers of lesser yam on mounds. Approximately 1800 - 2700 kg of

seed materials are required to plant one hectare. After planting the tubers, completely cover them with soil. Mulching

hastens sprouting, control weed growth, regulate soil temp and retain soil moisture.-1

Manures and Fertilizers: Apply cattle manure or compost @ 10 t ha at one month before planting. A fertilizer dose of -1

80 kg N, 60 kg P₂O₅ and 80 kg K₂O ha is optimum for yams. One-third of N (58kg of Urea), full dose of phosphorus -1 -1

(300 kg ha rock phosphate) and half dose of potash (67 kg ha of muriate of potash) are to be applied within a week

after sprouting. One third (⅓) N at 30days after planting and the remaining ⅓ N and ½ K needs to be applied two months

after planting. After weeding, top dressing of the fertilizers should be applied followed by earthing up and irrigation.

Management practices for intercrop: Yams can be raised as inter crops in coconut, arecanut, banana, rubber and

robusta coffee. In case of rubber and coffee, inter cropping should be restricted during the initial 3-4 years to avoid

serious deleterious effects on the growth and yield of both the crops. About 9000 plants can be accommodated at a


spacing of 90x90 cm in 1 ha of coconut plantation, leaving 2 m radius from the base of the palms. Both the main crop as

well as intercrop should be separately and adequately manured. Yam varieties such as Orissa Elite, Sree Latha, Sree

Keerthi and Sree Priya are suited for intercropping. Yams can also be intercropped in Nendran banana spaced at 3.6 x -1 -1

1.8m (1500 plants ha ), 3 rows of yams can be planted to accommodate 8000 plants ha . It was also found that the levels

of FYM, N and P to the intercrop as well as main crop could be reduced to half. But the quantity of potash should not be

reduced at any cost. Robusta banana can be planted at 2.4 x 1.8m to accommodate 2300suckers. In between 2 rows of -1

banana, 2 rows of yams can be planted to accommodate 6000 plants t ha . In Robusta banana Dioscorea system, banana

should be manured at the full recommended dosage and for yams, manuring at the ⅔ recommended level is sufficient. In

young rubber plantations, during the initial 3-4 years yams can be intercropped. But manuring at full dose should be

done for both the crops. It is possible to accommodate about 6000 yam plants in 1 ha of rubber plantation after leaving

1.5m radius from the base of the rubber plants When yams are intercropped in arecanut garden, about 7000 yams can be

accommodate at a spacing of 90 x 90 cm, leaving 1.0 m radius from the base of the palms.

Trailing: Trailing is necessary to expose the leaves to sun light as well as to increase the leaf area and to minimize the

anthracnose disease incidence. It is to be done within 15 days after sprouting by coir rope attached to artificial supports

in the open area or to the trees where it is raised as an intercrop.

Crop protection: Yam scale is found to occur on the tubers both under field and storage conditions. As a prophylactic

measure, dip the planting material in chloropyriphos 0.05% use scale free seed tuber for planting.

Anthracnose (leaf spot): It is caused by Colletotricum gloeosporiodes Penza. Among various Dioscorea species, D.

alata is very susceptible to anthracnose where as D. rotundata is more resistant. The disease appears as brown pin head

like spots on the leaves and stems. These spots become enlarged when the leaves approach full size, and they may

develop pale yellow margins. Sometimes the leaf spots run together to form large irregular blotches, the centers of

which may fallout giving a shot hole effect. Infected leaves usually fall off.

This disease can be managed by adopting crop rotation, fallowing removal of debris, planting of healthy material and

destruction of infected cultivars. Ploughing immediately after harvest also helps to reduce the inoculums. Spraying

Dithane M-45 (0.2%) and Bavistin (0.25%) reduces disease severity.

Harvesting: Greater yam and white yams become ready for harvest by 8-9 months after planting as the whole plant will

be dried. Lesser yam takes 8-9months for attaining maturity. Carefully dig out the tubers without causing injury.

Yield: Usually the farmers cut the top apical portion of the tubers and kept for seed material for the next season and the

remaining tubers used for sale in the market. Greater yam recorded a tuber yield of 20-50 t/ha based on good -1

management practices. It shows a potential yield up to 60-80 t ha with a net profit of Rs. 50,000 to 1,00,000/- from one

acre of yam field.

Elephant Foot Yam

Elephant foot yam (Amorphophallus paeoniifolius) is basically an underground stem tuber. Its cultivation is more or

less limited to India, Philippines, Indonesia, Sri Lanka and South East Asia. It has high dry matter production capability

per unit area than most of the other vegetables. It is a popular tuber crop and is grown as a vegetable in many parts of

India, especially South, East and Northern states. It is remunerative crop and is hence profitable. Elephant foot yam is

spreading larger area in Tripura during recent years due to its wide acceptability by the consumers as a vegetable crop.

Elephant-foot yam is widely used in Indian medicine and is recommended as a remedy in all three of the major Indian

medicinal systems: Ayurveda, Siddha and Unani (Khare, 2007). The corm is prescribed for bronchitis, asthma,

abdominal pain, emesis, dysentery, enlargement of spleen, piles, elephantiasis, diseases due to vitiated blood, and

rheumatic swellings. Pharmacological studies have shown a variety of effects (Wu and Zhu, 1999) specifically

antiprotease activity, analgesic activity, and cytotoxic activity (Das et al., 2009). In addition it has been found to be a

potentiator for further reducing bacterial activity when used with antibiotics (Dey et al., 2011). Along with other


therapeutic applications, the Ayurvedic Pharmacopoeia of India indicates the use of corm (Ravi et al., 2009) in prostatic

hyperplasia. The corm contains an active diastatic enzyme amylase, betulinic acid, tricontane, lupeol, stigmasterol,

betasitosterol and its palmitate and glucose, galactose, rhamnose and xylose.

Climate and soil: Amorphophallus is a tropical/ sub-tropical crop and hence thrives well under warm humid climate

with a mean annual temp. of 30° - 35ºC and a well distributed rainfall of 1000 - 1500 mm spread over a period of 6-8

months. It grows well on a variety of soils but well drained sandy loam or sandy clay loam soil with a near neutral soil

reaction is ideally suitable for bulking of the crop. The soil should be rich in organic matter with adequate amount of

available plant nutrients to realize higher productivity.

Planting season: Amorphophallus undergoes a dormancy period of 45-60 days. Traditionally farmers take advantage

of the dormancy period by planting during March-May, so that the setts would sprout with the pre monsoon showers. As

the South West monsoon starts early in NEH region, the rhizomes can be planted immediately with the pre monsoon

rains probably in the months of second fortnight of February to first fortnight of April.

High yielding cultivar: A selection of (AM-IS) from the indigenous germplasm collection of elephant foot yam with -1an average yield of 42 t ha has been released under the name 'Sree Padma' for general cultivation in Kerala. “Sree

-1Athira” is a genetically improved variety with good cooking quality and high yield (40 t ha ) in 9 months. The variety

'Gajendra' released from Acharya NG Ranga Agricultural University, Andhra Pradesh become popular all over India, -1

having a yield potential of 40-60 t ha .

Planting method: A good soil turning plough followed by pit formation is the traditional method of land preparation

for Amorphophallus. A pit size should be 45x45x45cm. The top soil is then mixed with farm yard manure or compost (2--13 kg pit ) in the pit prior to planting. The planting material is placed vertically in the pits and is then covered with soil

and compacted lightly. Amorphophallusis planted shallow as deep planting would interfere with harvest operations,

besides, most of its feeder roots are found on the surface. A comparatively wider spacing of 90x90cm has been

recommended for planting Amorphophallus.

Planting material: Amorphophallus corm is cut into setts of 500g, each bearing a portion of the central bud. Whole

corms of size (500g) if available can also be used as planting material. Rapid seed corm production technique evolved at

ICAR-CTCRI suggests use of cormel and mini sett transplants of 50-100 g size as planting material at a closer spacing

of 45x30cm.

Seed treatment: Prepare cow dung slurry by mixing fresh cow dung with sufficient water in a drum or container, add -1 -1 -1Mancozeb @ 2-3 g kg seed material along with Chloropyriphos @ 1 ml L or Imidacloprid @ 0.5 ml L . The cut pieces

of elephant foot yam were uniformly mixed with the cow dung slurry and kept for 4-5 hr. Then take out the rhizome

pieces from the container along with the cow dung slurry coating and dried under the sun light.

-1Manures and Fertilizers (sole crop): Apply FYM/ compost @ 2.0-3.0 kg pit at the time of planting. Applyfertilizers

-1@ 30 kg N, 60 kg P₂O₅ and 40 kg K O ha at 45 days after planting along with weeding and intercultural operations. Top 2

-1 -1dress with 25 kg N & 25 kg K₂O ha at one month and 25 kg N & 25 kg K₂O ha at 2 months after planting.

Management practices for intercrop: Amorphophallus can be intercropped profitably in coconut, arecanut, rubber,

banana and robusta coffee plantation. About 9000 plants can be accommodated at a spacing of 90x90cm in 1 ha of -1

coconut garden, leaving 2m radius from the base of the palms. Half the quantity of FYM (12.5 t ha ) and one third of a

NPK dosage (27:20:33) will be sufficient for an intercrop of Amorphophallus in coconut garden.

For intercropping Amorphophallus in Nendran banana, banana should be planted at 3.6x1.8m spacing to accommodate -11500 plants ha in between 2 rows of banana, 3 rows of Amorphophallus can be grown at a spacing of 90x90 cm to

-1accommodate 8000 plants ha , leaving 45 cm from the base of banana. For the crops FYM, N and P can be reduced to

half, whereas the entire quantity of K should be applied, care should be taken to manure both the main crop as well as the


intercrop separately and adequately while intercropping Amorphophallus with arecanut, rubber and robusta coffee.

Intercultural operations

Mulching: Mulching immediately after planting of elephant foot yam perhaps one of the most important cultural

operations in Amorphophallus, which will not only conserves the soil moisture and regulates the soil temperature,

suppress the weed growth and hastens the sprouting of Amorphophallus. Use either green or dried leaves for mulching.

Weeding: If proper mulching is done at planting, weeds would be suppressed to a large extent. Despite this one or two

manual weedings could be given, first at 45days after planting and the second, one month after the first weeding.

Fertilizer application can be combined with these intercultural operations.

Irrigation: Amorphophallus is mostly raised as a rainfed crop. However, irrigation is required when monsoon fails

specially in eastern India, where it is grown on a large scale. In the East and West Godavari districts of Andhra Pradesh it

is extensively grown in paddy and sugar cane fields, where water requirement of the crop is met through canal

irrigation. However, stagnation of water is harmful to the crop.

Crop protection

Collar root: The disease is caused by a soil borne fungus Schlerotium rolfsii. Water logging, poor drainage and

mechanical injury of collar region favour the disease incidence. Brownish lesions first occur on collar regions which

spread to the entire pseudo stem and cause complete yellowing of the plant. In severe cases plant collapses leading to

complete crop loss.

The disease can be managed by using disease free planting material removal of infected plant material improving

drainage conditions. Incorporation of organic amendments like neem cake, use of bio control agents like Trichoderma

harzianum drenching the soil with 0.2% Captan will effectively control the disease.

Harvesting: Amorphaphollus becomes ready for harvest in about 8-9 months after planting coincide with the

senescence of the plant. The crop attains maturity when total senescence takes place. Rhizome yields varied from 20--1 -1

50 t ha based on native soil soil fertility and management practices. Its potential yield varied from 50-80 t ha .

Colocasia

Taro or colocasia or cocoyam (Colocasia esculenta) is a tropical food crop with high potential because of the high yield

of the roots (or corms) and foliage. It is believed to be one of the earliest cultivated plants. Worldwide it grows in an area -1of 1.66 m ha with a production of 10.64 mt and productivity of 6.41 t ha (FAO, 2018). Cultivation of taro is widespread

in India, Burma, China, Japan, Hawaii, Egypt, Africa and the Caribbean. Africa contributed 89% area (1.47 m ha) and -174% production (7.87 mt) and low productivity of 5.36 t ha of colocasia, whereas Asia contributed 8.4% area and 22%

-1production with highest productivity of 16.79 t ha . Major taro producing countries in the world are Nigeria (3.30 mt),

China (1.95 mt), Cameroon (1.90 mt), Ghana (1.46 mt), Papua New Guinea (0.272 mt), Madagascar (0.23 mt) and -1

Rwanda (0.223 mt). India occupies 40,000 ha with a production of 1.0 mt and productivity of 25 t ha .

Colocasia is nutritionally rich in carbohydrates and minerals, however, its composition varies according to the variety

and country of origin. Numerous epidemiological studies suggest that diets rich in phytochemicals and antioxidants

execute a protective role in health and disease. Taro leaf silage could replace up to 70-75% of the fish meal protein, with

higher feed intakes and N retention than with 100% of the protein from fish meal or from taro leaf silage (Buntha et al.,

2008). The mature corms and young shoots of edible aroids are mostly used as boiled vegetables, but the corms are also

roasted, baked, or fried and can be eaten alone or with stew. Taro chips are another important secondary product. The

corms supply easily digestible starch and are known to contain substantial amounts of protein, vitamin C, thiamine,

riboflavin, niacin and significant amounts of dietary fibre (Niba, 2003). Leaves of taro are cooked and eaten as

vegetable. Cocoyam flour can be used for the preparation of soups, biscuits, bread, beverages, and puddings. Research

and development of root and tuber crops in general, and cocoyam in particular, have been neglected because only 10%

of the world populations, mainly living in the developing tropical countries, use root and tuber crops as staple foods.


Since the cultivation of taro is being concentrated globally, the present review is a compilation of chemical constituents,

and alternative uses of colocasia.

Planting season: Under rainfed condition, plant the cormels/ corms during April to June is optimum. If grown as

irrigated crop, it can be raised throughout the year.

Improved varietiesSl. No. Cultivar Duration (Days)

Yield -1(t ha )

Special features

All parts of the plant namely, leaf, petiole, corm and cormels

(side tubers) are non acrid. Corms are big and the cormels are

medium in size. The cormels have good cooking qualities and

taste: starch content 15% and protein 2.5%.

Sree Rashmi 7-8 15-20

Corms are relatively big and cormels are small and more in

number. Cormels have good cooking quality and taste. Starch

content 16-17% and protein 2-3%.Sree Pallavi 6-7 15-18

A tall variety with large number of small sized tubers. Protein

2-3%, resistant to leaf blight suitable for uplands and

lowlands.Muktakeshi 6-7 15-18

Clonal selection from variety Kantilo local suitable for

waterlogged conditions of Odisha.Pani Saru-1 6-7 15-16

Pani Saru-2 6-7 12-14Clonal selection from variety Begunia local suitable for water

logged conditions of Odisha.

Sree Kiran 6-7 16-18 First Taro hybrid from India, good cooking quality.

1

2

3

4

5

6

Planting material

Cormels as well as the mother corms can be used as planting materials, but cormels are ideal weighing about 20-30g

form good planting material.

Three strategies are currently available for the rapid multiplication of planting material. The first is to use a minisett

technique analogous to the same technique used for yams. Essentially, small corm pieces 30-50g in weight are protected

with seed dressing. They are sprouted in a nursery, and then planted in the field. The resulting small corms and suckers

are used as subsequent planting material. The minisett technique can be carried out by the farmers themselves, since the

level of technology required is well within their competence.

Land preparation: According to soil type and management practices, different methods of land preparation may be

followed. In sandy loams, pit method is better where as in alluvial soils, raised mounds or beds are preferred. Under

irrigated conditions, ridge and furrow system may be adopted.

Method of planting: Plant the cormels at a spacing of 50x30 cm about 67,000 seed tubers are required to plant one

hectare. The cormels may be planted to a depth of 2.5 - 7.5 cm. If planted at recommended spacing, approximately

800kg of planting materials would be required to cover one hectare.

Mulching: Planted seed tubers take 30 to 45 days for sprouting. Mulching helps to hasten sprouting, controlweed

growth, regulate soil temp and retain soil moisture. The planted seed tubers need to be mulched with green or dry leaves.


Manures and Fertilizers: The majority of taro growers in the Asia/Pacific region, especially thoseproducing taro for

subsistence, do not use any fertilizer. Some even believe that fertilizers diminish the quality and storability of their taro.

All the same, taro has been found to respond well to fertilizers and to organic sources. The specific fertilizer types and

quantities recommended vary widely from place to place. In general, it is best to apply the fertilizer, compost or manure

as a split dose. The first portion is applied at planting, possibly incorporated into the soil during land preparation. This

first dose promotes early plant establishment and leaf elaboration. The second dose of fertilizers will be applied 3-4

months later when the corm enlargement is well under way. Splitting the fertilizer dose minimises the losses due to

leaching which is potentially high in the high-rainfall areas where taro is produced.

Malnourished taro exhibits certain deficiency symptoms. Potassium deficiency causes chlorosis and necrosis of leaf

margins and death of the roots. Zinc deficiency results in inter-veinal chlorosis and stunted growth, while for

phosphorus, a leaf petiole content below 0.23% signals the need to apply fertilizer. Various other nutritional

deficiencies and toxicities of taro have been elaborated by O'Sullivan et al. (1995).

Apply 12 tons of FYM per hectare and mix it with the soil prior to planting. Taro requires a fertilizer dose of 80 kg N, 40 -1kg P₂O₅ and 100 kg K₂O ha in two or three split doses. One-third dose of Nitrogen (60 kg of urea or 135 kg of

Ammonium sulfate) 200 kg of rock phosphate and ⅓ dose of potash (55 kg of muriate of potash) are to be applied at two

weeks after sprouting. The remaining dose of nitrogen and potash may be applied in two equal split doses at monthly

intervals after application of first dose of fertilizers. The weeding and earthling up operations are to be done along with

the application of fertilizers. Small, inefficient suckers from the mother plant have to be removed along with second

weeding and earthling up operations.

Crop protection: Aphids and worms are important pests attacking the leaves. The other pests include spider mites,

thrips, grasshoppers, scale insects and mealy bugs. These can be controlled by spraying 0.05%. Quinalphos or

Dimethoate. Mealy bugs and scale insects damage cormel and corms and hence select the cormels free from the

diseases or pests for planting. If infested the seed cormel should be dipped in Dimethoate or Chloropyriphos 0.05% -1solution for 10 min before planting. Taro corm borer controlled by spraying of 0.02% Chloropyriphos 20 EC (1 ml lit )

-1or 20% SL of Imidachloroprid (0.3 ml lit ).

Leaf blight disease: Leaf blight (Phytophthora colocasiae) symptoms appear as small, dark, round spots on the upper

surface and dark lesions on the underside of the leaf.

Integrated disease management for colocasia leaf blight includes the following

l Use healthy and disease free planting material.

l Use disease resistant varieties like Muktakeshi.-1

l Treat the seed tubers with Mancozeb @ 2 g kg of tubers. th

l Plant early maturing varieties like Nadia local and Kadma local during May or after 15 July in order to escape the

disease.

l Preventive spraying of the crop with Mancozeb (0.2%) 3-4 sprays or Metalexyl 0.05 % 2-3 sprays give effective

and economic control.

Harvesting: For dry land taro, maturity for harvest is signalled by a decline in the height of the plants and a general

yellowing of the leaves. The same symptoms occur in flooded taro, but are less distinct. Because of the continuous and

abundant water supply, the root system of flooded taro remains alive and active, and leaf senescence is only partial.

Dry land taro takes 5-12 months time from planting to harvest and 12-15 months for flooded taro. Harvesting of taro

depends on the cultivar and the prevailing conditions during the season.-1 -1Taro recorded a cormel yield of 15-30 t ha . Potential yield varied from 30-50 t ha .


Arrowroot

Arrowroot (Maranta arundinacae) commonly known as “West Indian Arrowroot” is an erect herbaceous plant

belonging to the family Marantaceae. Arrowroot is primarily grown for its quality starch which is valued as food stuff

particularly for infants and invalids. The crop is native of tropical America. In India, it is being grown in North Eastern

states, West Bengal, Assam and in south India mostly in Kerala as a rainfed crop.

Climate and soil: The crop grows best at temperature of 20º - 30⁰C. A minimum annual rainfall of 950-1500 mm is

required. The crop thrives best in deep, well drained, slightly acid loam soils under partial shade.

Planting method: Plough the land to obtain a fine tilth. Prepare raised beds of 15-20 cm height and convenient length

and breadth. Plant the rhizome bits 30 cm apart at a depth of 5.0 - 7.5 cm and cover with soil. Trials conducted at ICAR -

Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala, India revealed that planting at a spacing of 30 x

15cm produced significantly higher tuber yield. Its clumps also used as planting materials. Plant two clumps at a

distance of 45cm.

Planting material: Arrowroot does not set seeds and is normally propagated from small pieces of rhizomes 4-7 cm in

length with 2-4 nodes known as bits. Suckers also occasionally used for planting after raising them in the nursery.

Theses suckers give rise to new plants which are uprooted and cut off to retain 10cm of the shoot intact with roots. The -1

requirement of planting material is about 5.5 t ha .-1

Manures and Fertilizers: Application of 10 t ha of FYM or compost is suitable for arrowroot cultivation. Application -1

of 50kg N, 25kg P₂O₅ and 75kg K₂O ha is required to get higher yields. Presence of good amount of organic matter in

the soils is beneficial to realize higher crop yields.

Intercultural operations: It is essential to keep the field clean and free of weeds during the first 3 - 4 months. Earthling

up should be done along with weeding. Mulching with green or dried leaves significantly influences tuber yields.

Irrigation: The crop is grown purely as a rainfed crop. However, if dry spell occurs during the initial 3-4months,

supplementary irrigation at weekly intervals become necessary.

Harvesting: The crop attains maturity in 10-11 months after planting. Maturity is indicated by yellowing, wilting and

drying up of the leaves. At this stage, the plants are dug out and the rhizomes are separated. On an average a yield of 20--125 t ha can be realized. The starch extracted from the tubers is having high market value as it is raw material for various

industrial products as well as some of the entrepreneurs exporting the quality starch and earning higher net profit.

Yam Bean

Yam bean (Pachyrrhizus erosus L) belongs to the family Leguminous and sub family Fabaceae (Papilionaceae). It is

popularly known as Mishrikhand in Hindi. Yam bean is a starchy root crop with comparatively high sugar content and

moderate in ascorbic acid. In India tender tubers are consumed as a vegetable. Young tubers are crisp, succulent and

sweet and are highly preferred for salad making. The mature seeds have high content of alkaloids and insecticidal

properties. In many developed countries the tubers are processed, canned and many sweet preparations are made. The

crop has been cultivated in Mexico and South America from pre-Colombian period has originated from hot moist

region of the river Amazon. The crop is now being cultivated in Philippines, china, Indonesia, Nepal, Bhutan, Burma

and India. In India it is grown in parts of west Bengal, Bihar, Odisha and Assam.

Climate and Soil: Yam bean requires a hot humid climate and it adapts well in sub tropical and hot temperature frost-

free zones. Yam bean requires about 14-15 hours of photoperiod for good vegetative growth, however, shorter days are

required for better tuberization. A well distributed rainfall during the growth period is required for optimum tuber yield.

Fertile, well drained, sandy loam soil is best suited for cultivation of yam bean. The crop adapts well to loamy and clay

loam soil. It can tolerate higher clay content if the soil is well drained with good humus content. Water logging

adversely affects yam bean cultivation. Optimum pH requirement is 6-7.

Planting season: Traditionally yam bean is shown during June - July with the onset of rain in North-eastern India and is


usually harvested in December - January.

Planting method: Deep ploughing of land followed by planking pulverizes the soil as well as conserves moisture. Yam

bean seeds dibbled at the rate of 3-5 seeds per hill. Prepare mounds at a spacing of 0.75 - 1.00 m with 15 cm height.

Planting of the seeds on ridges results in better yield.

Planting material: Yam bean is usually raised by seed. The seed rate varies according to the spacing adopted. Normal -1seed rate is 10-15 kg ha .

-1Manures and Fertilizers: Application of 15-20 t of FYM or compost and a fertilizer dose of 80:40:80 kg NPK ha has

been recommended for North Bihar for getting optimum yields. In Tamil Nadu and West Bengal, yam bean was found to -1

perform well at a fertilizer dose of 80:60:80 kg NPK ha . Entire dose of P and K has to be applied at the time of planting

along with half the dose of nitrogen the remaining quantity of N is top dressed at 40-50 days after sowing along with

inter culturing and earthing up.-1

Nutrient management: Ramaswamy et al. (1980) suggested that a fertilizer dose of 80:60:80 kg NPK ha is optimum -1

in Tamil Nadu. In West Bengal, NPK @ 80:80:80 kg ha is recommended (Sen and Mukhopadhyay, 1989). Mondal and -1

Sen (2006) found that by fertilizing yam bean with NPK @ 50:25:50 kg ha , the seed yield could be increased. Despite

the earlier evidences that there was no need to supply additional N to this leguminous crop, many workers have found

later that yam bean responded positively to application of N fertilizers. Under the aegis of All India Co-ordinated

Research Project on Tuber Crops, Rajendra Agricultural University, Dholi (North Bihar) has standardized the nutrient -1 -1

requirement for yam bean as FYM or compost @ 15-20 t ha along with NPK @ 80:40:80 kg ha .

Intercultural operations: Normally yam bean starts flowering at 75 days after sowing. It is desirable to remove the

flowers for getting better tuber yield. There is significant negative correlation between tuber yield and pod formation. It

has been observed that spraying 2,4-D @ 50 ppm at flower initiation stage causes dehiscence of flowers and results in

better tuber yield.

Irrigation practices: Normally there is no need to irrigate the crop which was planted during June-July. In case there is

scarcity of rains, irrigation is essential as yam bean requires lot of moisture. The crop planted during September needs

supplementary irrigation, so that the crop will not face moisture stress during tuberization. In the hilly tracts of NEH

region, it may establish without irrigation externally as it thrives well with the residual moisture. If drought spell

prevails continuously, the crop needs life saving irrigation as some farmers irrigating the rabi crops through 'Jalkund'

built on the top of the hillocks.

Harvesting: Yam bean will be ready for harvest in 150 days after sowing. Usually it is harvested on the occasion of

“Saraswati Pooja” because of market demand. If harvesting is delayed, cracking of tubers are more. Harvested tubers -1can be stored for 2-3 days without any deterioration. The average yield of local cultivars is 18-20 t ha while that of

-1improved varieties like Rajendra Mishrikhand is 36-40 t ha

References

1. Buntha, P., Borin, K., Preston, T.R. and Ogle, B. 2008. Effect of Taro (Colocasia esculenta) leaf silage as replacement

for fish meal on feed intake and growth performance of crossbred pigs. Livestock Research for Rural Development.

Volume 20, Supplement. Retrieved September 2, 2011.

2. Ceballos, H., Okogbenin, E., Pérez, J.C., Augusto, L., Lopez-Valle, B. and Debouck, D. 2010. Cassava. In: Root and

Tuber Crops. Bradshaw, J. E. (Ed.). Springer Science-Business Media, New York, USA, pp.53-96.

3. Dey, Y.N., De, S., Ghosh, A.K., Gaidhani, S., Kumari, S., Jamal,, M. 2011. Synergistic depressant activity of

Amorphophallus paeoniifolius in Swiss albino mice. Journal of Pharmacology and Pharmacotherapeutics 2 (2):

121-123.

4. FAO. 2018. Food and Agriculture Organization of the United Nations Statistical Year Book published by FAO,

Rome, Italy.


5. Jansson, R. K. and Ramon, K.V. 1991. Sweet potato pest management: A global overview. In: Sweet Potato Pest

Management: A Global Perspective. Jansson, R.K. & Ramon, K.V. (Eds.). West view press Inc., Boulder, CO. pp.

2-12.

6. Khare, C.P. 2007. Indian Medicinal Plants: An Illustrated Dictionary. Berlin: Springer Verlag.ISBN 978-0-387-

70637-5.

7. Laxminarayana, K., Burman, D., Singh, D.P. and Naskar, S.K. 2010. Effect of Salinity on Yield, Quality and Nutrient

Uptake of Sweet Potato in Coastal Saline Soils. Journal of the Indian Society of Coastal Agricultural Research

28(2): 1-5.

8. Laxminarayana, K. 2013. Impact of INM on Soil Quality, Yield, Proximate Composition and Nutrient Uptake of

Sweet Potato in Alfisols. Journal of Root Crops 39 (1): 48-55.

9. Laxminarayana, K. and Burman, D. 2014. Nutritional Response of Sweet Potato Genotypes on Saline Inceptisol.

Journal of Indian Society of Soil Science 62(1): 62-66.

10. Laxminarayana, K., Susan John, K., Mukherjee, A. and Ravindran, C.S. 2015. Long-Term Effect of Lime,

Mycorrhiza, and Inorganic and Organic Sources on Soil Fertility, Yield, and Proximate Composition of Sweet

Potato in Alfisols of Eastern India. Communications in Soil Science and Plant Analysis 46(5): 605-618

11. Lobenstien, G. 2009. Origin, distribution and economic importance. In: The Sweet Potato, Lobenstein, G. and

Thottappilly, G. (Eds.). Springer Science Publishers, pp. 9-12.

12. Meireles da Silva, R., Bandel, G. and Martins, P.S. 2003. Mating system in an experimental garden composed of

cassva (Manihot esculenta Crantz) ethnovarieties. Euphytica 134: 127-135.

13. Niba, L.L. 2003. Processing effects on susceptibility of starch to digestion in some dietary starch sources.

International Journal of Food Sciences and Nutrition 54: 97-109.

14. O'Keefe, D. M. and Sylvia, D.M. (1993). Seasonal dynamics of the association between sweet potato and vesicular-

arbuscular mycorrhizal fungi. Mycorrhiza 3(3): 115-122.

15. O'Sullivan J.N., Asher, C.J., & Blamey, F.P.C. 1995. Diagnostic criteria for nutritional disorders in taro. In:

Diagnosis and correction of mineral nutrient disorders of root crops in the Pacific (Eds., Asher, C.J. and Crasswell,

E.T.). Proceedings of Workshop, Nuku'alofa, Tonga 1995. ACIAR Proceedings No. 65. Australian Centre for

International Agricultural Research.

16. Pujol, B., Gigot, G., Laurent, G., Pinheiro-Kluppel, M., Elias, M., Hossaert- McKey, M. and McKey, D. 2002.

Germination ecology of cassava (Manihot esculenta Crantz Euphorbiaceae) in traditional agroecosystems: seed

and seedling biology of a vegetatively propagated domesticated plant. Economic Botany 56: 366-379.

17. Ravi, V., Ravindran, C.S. and Suja, S. 2009. Growth and productivity of elephant foot yam (Amorphophallus

paeoniifolius): An overview. Journal of Root Crops 35 (2): 131-142.

18. Wu, Xueqing and Zhu, Weifeng 1999. SummaryofPharmacologicalStudiesofAmorphophallusRiviers. LiShiZhen

Medicine and Materia Medica Research 10 (8): 631-632.


Tropical root and tuber crops are plants yielding starchy roots, tubers, rhizomes, corms and stems. They are used mainly

for human food (as such or in processed form), for animal feed and as raw material for starch, alcohol and fermented

beverages including beer. These crops play an important role in food security, nutrition and climate change adaptation.

These mainly include cassava (Manihot esculenta Crantz), sweet potato (Ipomoea batatas), taro (Colocasia esculenta),

yams (Dioscorea sp.), Elephant foot yam (Amorphophallus paeoniifolius), arrowroot (Maranta arundinacea) and

other minor root crops. Apart from their high water content (70-80 percent), these crops contain mainly carbohydrates

(16-24 percent of their total weight) with very little protein and fat (0-2 % each). Tuber crops have a higher biological

efficiency and show the highest rate of dry matter production per day per unit area among all the crops. The North

eastern hill (NEH) region has immense potential for tuber crops cultivation owing to diverse agro climatic condition,

varied soil and high rainfall with wide regional variation. Tuber crops such as sweet potato, taro, cassava, yam, elephant

foot yam are quite common among the native tribe of this region and is grown in kitchen garden often mixed with other

vegetables or collected from jungle.Tuber crops like cassava, taro and yam are common crops grown in the jhum or

shifting cultivation fields by the tribal people. Sweet potato and taro are grown considerably in the hills as well as in the

plains of Assam and Tripura. In its immense service to the nation, ICAR-CTCRI has contributed with more than 60

improved varieties of various tuber crops for the benefit of tuber crops farmers and starch-based Industries.

Given below are the detailed descriptions of improved varieties of sweet potato, yams and edible aroids suitable for

north eastern hill region.

1. SWEET POTATO

Sweet potato (Ipomoea batatas) of family Convolvulaceae is a dicotyledonous plant grown across different agro

climatic zones such as tropical, sub tropical and frost free temperate climatic conditions. It can grow at altitudes ranging

from sea level to 2500 meters and has wide spectrum of variability in skin and flesh colour starting from white to yellow,

orange and deep purple (Hijmans et al. 2002).

Major breeding objectives

l High yield

l Resistance to pests and diseases particularly for resistance against sweet potato weevil

l Better culinary quality and increase in nutritional value especially for high carotene and high protein contents

l Early maturity, preferably less than 90 days

l Compact bushy plant type

l Shade tolerance and adaptability to intercropping systems

l Improved tuber quality with low sugar and high starch

l High starch content for industry

l Dual purpose clones which can be used as fodder crop with reasonable yield

l High keeping quality

l Wider adaptability and photo insensitivity

Sweet potato varieties released by ICAR-CTCRI

The brief description of sweet potato varieties released by ICAR-CTCRI is listed below

HIGH YIELDING VARIETIES OF TUBER CROPS SUITABLEF OR NORTH EASTERN REGION

Visalakshi Chandra C., Sheela M. N., Shirly Raichal Anil, Asha Devi A., Sunitha S. and Suresh Kumar J.Division of Crop Improvement, ICAR-Central Tuber Crops Research Institute, Sreekaryam,

Thiruvananthapuram, Kerala, India


Sree Bhadra

Sree Bhadra was released in 1996. It is a selection from seeds introduced from Nigeria in 1984 with 90 days duration. It -1 -1has average yield of 20-22 t ha with a potential yield up to 27 t h t ha . The variety is suitable for Kerala, Maharashtra,

Bihar and Madhya Pradesh. It has a semi spreading habit with greenish brown vine with dark brown emerging leaves,

broad cordate leaves and profuse flowering The tubers are spherical in shape with light pink skin and cream flesh. It has

excellent cooking quality with carotene content of 800-1000 IU /100g and can be used as a trap for root knot nematode

(Meloidogyne incognita)

Gouri

Gouri was released in 1998. It is a hybrid between H-219 x H-42 with 110-120 days duration. It has average yield of 19 t -1 -1

ha with a potential yield up to 30 t ha . The variety is suitable for Odisha. It has a semi erect habit with slightly purple

emerging leaves, simple leaf with 5-6 lobes and profuse flowering. The tubers are obovate to round elliptic in shape with

purple red skin and deep orange flesh. It has excellent cooking quality with high carotene content of 7500-9100 IU

/100g and can tolerate tolerate mid season moisture stress. It is suitable for both kharif and rabi seasons.

Sankar

Sankar was released in 1998. It is a hybrid between H-219 x S-73 with 120 days duration. It has average yield of 13.7 t -1 -1ha with a potential yield up to 27 t ha . The variety is suitable for Odisha. It has a spreading habit with green vine and

green with purple edged emerging leaves, hastate leaf and green petiole with purple near the base. IT has moderate

flowering. The tubers are elliptical in shape with red skin and pale-yellow flesh. It has excellent cooking quality with

starch content of 2.5 -24%.

Kalinga

It was released in 2004. It is a selection from open pollinated seed with 105-110 days duration. It has average yield of -1 -1

17.2 t ha with a potential yield up to 28.4 t ha . The variety is suitable for Odisha. It has a spreading habit with green

vine, purple edged green emerging leaves, deep lobed leaves and moderate flowering. The tubers are round to elliptical

in shape with purple red skin and white flesh. It is a medium duration variety with excellent cooking quality and high

starch content (28%) and sugar content (2.5-3.3%) It can be used as food, fodder and for starch extraction.

Goutam

It was released in 2005. It was generated from polycross and Dhenkanal local, a popular land race was the female

parent. It matures in 105-110 days. It has a spreading plant type with purple vine and light purple emerging leaves. The

leaves are triangular with purple edged green petiole. The tubers are round to ovate in shape with white skin and cream

flesh. It has excellent cooking quality and is suitable kharif and rabi season and is well accepted by farmers of hilly and

coastal areas of Odisha.

Sourin

It was released in 2005. It was generated from polycross and accession no. 1162 was the female parent. It matures in -1 -1

105-110 days. It has an average yield of 16.2 t ha and potential yield of 29.7 t ha . It is suitable for upland and hilly areas

of Odisha. It has a spreading plant type with purple vine and purple green emerging leaves. The leaves are lobed with

green petiole with purple spot throughout. The tubers are round to elliptical in shape with red skin, white rind and

creamy white flesh. It is suitable for both kharif and rabi season and is well accepted by farmers of hilly and coastal areas

of Odisha.

Kishan

It was released in 2005. It was generated from polycross and accession no. 1016 was the female parent. It matures in -1 -1110-120 days. It has an average yield of 17 t ha and potential yield of 26 t ha . It is suitable for upland and hilly areas of

Odisha. It has a semi compact plant type with greenish purple vine and green emerging leaves with purple margin. The


leaves are triangular with green petiole purple near leaf base. The tubers are elliptical in shape with reddish purple skin,

white rind and creamy white flesh. It is suitable for food, fodder and starch extraction. It is a high yielder with 18.2%

extractable starch and can withstand mid season drought, performs better in sandy loam and black sandy soils.

Bhu Sona

It was released in 2017. It is a clonal selection of open pollinated seedling progenies of exotic source. It matures in 105--1

110 days. It has an average yield of 20-24 t ha . It is suitable for Odisha. It has a spreading habit with pubescent, purple

vine with shallow grooves and green emerging leaf. The leaves are triangular with green petiole and has profuse

flowering. The tubers are round elliptical in shape with yellow skin and dark orange flesh with β carotene 19100-20800

IU/100g fresh weight. Extractable starch 19-20%, tolerant to salt stresses 6-8.0 dSm-1 and field tolerant to weevil and

suitable for processing.

Bhu Kanti

It was released in 2017. It is a clonal selection from exotic source. It matures in 105-110 days. It has an average yield of -122-24 t ha . It is suitable for Odisha. It has a spreading habit with green vine with many purple spots and dark green

emerging leaves. The leaves are triangular and the flowering is profuse. The tubers are elliptical in shape with light

yellow skin and orange flesh with β carotene of 10833 IU/100g fresh weight. It is tolerant to mid season drought and salt

stress.

Bhu Ja

It was released in 2017. It is a clonal selection from introduced CIP line. It matures in 100-110 days. It has an average -1

yield of 20-22 t ha . It is suitable for Odisha. It has a semi compact plant type with green vine and emerging leaves. The

leaves are triangular and the flowering is profuse. The tubers are round elliptical in shape with pink skin and orange flesh

with β carotene content of 9160-10670 IU/100g fresh weight; starch content of 16.6-17.2% and total sugar content of

2.4-3.0%. It is tolerant to salt stress 6-8.0 dSm-1. It has good cooking quality.

Bhu Krishna

Bhu Krishna was released in 2017. It is a clonal selection of open pollinated seedling progenies of exotic source. It -1matures in 110-120 days. It has an average yield of 18-22 t ha . It is suitable for Odisha. It has a semi compact plant type

with green pubescent vine having purple nodes, purple edged green emerging leaves and has lobed leaves. The

flowering is sparse. The tubers are long elliptical in shape with dark purple skin and dark purple flesh containing

90mg/100g anthocyanin. It is highly tolerant to weevil and salt stress. The extractable starch content is 20-21%.and is

suitable for processing.

Bhu Swami

Bhu Swami was released in 2017. It was obtained by open pollination and clonal selection from exotic lines. It matures -1

in 105-110 days. It has an average yield of 20 t ha . It is suitable for Odisha. It has a semi compact plant type with green

vine having purple spots and emerging leaves having purple veins on upper surface. The leaves are triangular and the

flowering is profuse. The tubers are round in shape with dark white skin and white flesh. It is tolerant to mid season

drought and has excellent cooking quality. The extractable starch content is 21%.and is suitable for processing.

Bio-fortified varieties of sweet potato varieties


2. YAMS

Yams (Dioscorea spp.) are herbaceous climbers belonging to genus Dioscorea cultivated widely in tropics for the

starchy tubers. Dioscorea alata, Dioscorea rotundata, Dioscorea esculenta, Dioscorea bulbifera, Dioscorea

pentaphylla, Dioscorea steriscus and Dioscorea sansibarensis are some of the known species of Yam (Washaya et al.

2016).

Breeding objectives

l High and stable tuber yield

l Tuber shape, size, storability, dry matter content and food quality

l Resistance to biotic stresses (e.g. viruses, anthracnose, nematodes)

l Tolerance to abiotic stresses (e.g. low soil nutrients, drought)

l Suitability to major cropping systems (e.g. plant architecture, and maturity period).

2.1 Yam varieties released by ICAR-CTCRI

2.1.1 Greater Yam (Dioscorea alata)

Sree Keerthi

It was released in 1987 as a clonal selection from germplasm with 9-10 months duration. It has an average yield of 25- -1 -130 t ha and potential yield of 44 t ha . It has starch content of 20-22 %. It is a climber twining to right, male parent

with green vine. Emerging leaves light brown and mature leaves are sagittate with green petiole. Tubers are large,

conical, rough with grayish brown skin, yellow cortex and white flesh. Key traits: Resistant to anthracnose disease;

suitable for intercropping in banana and coconut

Sree Roopa

It was released in 1987 as a clonal selection from germplasm with 9-10 months duration. It has an average yield of 25- -1 -130 t ha and potential yield of 54 t ha . It has starch content of 16-18 %. It is a climber twining to right, female parent

with green vine and purple ridges. Emerging leaves are green and petiole has purple base, middle green and light

purple tip. Tubers are digitate, smooth with black skin, purple cortex and white flesh color. Key traits: Excellent

cooking quality, medium protein content- 1.0 to 1.5%, resistant to scale insect during storage

Sree Shilpa -1

It is a hybrid (Da -140 x Sree Keerthi) released in 1998 with 8 months duration. It has an average yield of 28 t ha and -1

potential yield of 40.4 t ha . It has starch content of 17-19 %. It is a climber twining to right, male parent with green

vine. Emerging leaves are green and mature leaves are cordate with overlapping lobes and purple petiole. Tubers are

Swollen, smooth with black skin, yellow cortex and white flesh color. Key traits: Medium sized tubers, World's First

hybrid released in D.alata.

Sree Karthika

It was released in 2004 as a clonal selection from germplasm with 9-10 months duration. It has an average yield of 30 t -1 -1ha and potential yield of 46 t ha . It has medium starch content of 21.4% and protein content of 2.5%. It is a

climber twining to right, male parent with green vine. Emerging leaves are purple and mature leaves are narrow and

cordate. The petiole has purple base with green middle and top portion. Tubers are medium long, oval with grayish

black skin, pink cortex and white flesh color. Key traits are excellent cooking quality and field tolerance to anthracnose

disease.

Orissa Elite-1

Released in 2005 as a clonal selection from germplasm with 6-7 months duration. It has an average yield of 25 t ha -1

and potential yield of 30 t ha . It has medium starch content of 20.1% and total sugar of 3.8%. It is a climber twining to

right, male parent with green vine. Emerging leaves are light brown and mature leaves are long cordate with purple


petiole. Tubers are medium long, oval with grayish black skin, pink cortex and white flesh color. Key traits are field

tolerance to scale insects and mealy bugs.

Sree Swathy-1

Released in 2014 as a clonal selection from germplasm with 9 months duration. It has an average yield of 25 t ha and -1potential yield of 30 t ha . It has medium starch content of 20.02%, high protein (16.94% DW) and ascorbic acid

content of 6.96mg/100g DW. It is a climber twining to right with green vine. Emerging leaves are green and mature

leaves are cordate with green petiole and purple wings. Tubers are medium long, conical to irregular with dark brown

skin, yellow cortex and white flesh color. Key traits are drought tolerance and resistance to anthracnose disease. Good

cooking and nutritional quality.

Sree Neelima-1

Released in 2014 as a clonal selection from germplasm with 9 months duration. It has an average yield of 33 t ha and -1

potential yield of 45 t ha . It has low starch content of 18.1% FW, medium crude protein (3.28% FW). It is a climber

twining to right with purple vine. Emerging leaves are purple and mature leaves are broad and cordate. Petiole has

green base and tip and purple wings. Tubers are conical with dark brown skin, dark purple cortex and light purple flesh

color. Key traits are good cooking and nutritional quality.

Purple fleshed anthocyanin rich Sree Neelima

Sree Nidhi-1

Released in 2017 as a clonal selection from germplasm with 8-9months duration. It has an average yield of 35 t ha and -1

potential yield of 50 t ha . It has starch content of 23.2% FW, medium crude protein (2.5% FW). It is a climber

twining to right with green vine. Emerging leaves are light brown and mature leaves are narrow cordate and light green

in color. Petiole is green with purple end. Tubers are cylindrical with light pink cortex and white flesh color. Key

traits are field tolerance to anthracnose and good cooking quality. Optimum tuber size with less apical portion and

therefore less wastage and higher market price.

Bhu Swar-1

Released in 2017 as a clonal selection from germplasm with 8-9months duration. It has an average yield of 20-25 t ha -1

and potential yield of 30 t ha . It has low starch content of 18-20%. It is a climber twining to right with green vine with

purple wings. Emerging leaves are purplish green and mature leaves are sagitate with overlapping base. Petiole is

green with purple base and wings. Tubers are long cylindrical to irregular with brown skin, yellow cortex and cream

flesh color. Key traits: excellent cooking quality.

2.1.2 White Yam (Dioscorea rotundata )

Sree Priya

Released in 1987 as a seedling selection from African variety “Umidika” with 9-10 months duration. It has an average -1 -1yield of 35 t ha and potential yield of 48 t ha . It has medium starch content of 19-21%. It is a climber twining to


right with spiny green vine with purple wings. Emerging leaves are green and mature leaves are cordate with waxy

margin. Tubers are cylindrical and smooth with brown skin and white flesh color. Key traits: drought tolerance, good

flavor, suitable for intercropping with coconut and banana.

Sree Subhra

Released in 1987 as a seedling selection from African variety “lwo ” with 9-10 months duration. It has an average yield -1 -1of 35 t ha and potential yield of 48 t ha . It has medium starch content of 21-22% and 1.8-2.0% protein. It is a climber

twining to right with spiny green vine with purple wings. Emerging leaves are green and mature leaves are cordate

with wavy margin. Tubers are cylindrical and hairy with brown skin and white flesh color. Key traits: drought tolerance

and excellent cooking quality.

Sree Dhanya -1

Released in 1993 as a seedling selection with 9 months duration. It has an average yield of 25 t ha and potential yield -1

of 39 t ha . It has medium starch content of 24% and 2.0 -2.5 % protein. It is dwarf, bushy, non climber of 30-50 cm

height and male. Emerging leaves are green with light green petiole. Tubers are cylindrical and partly hairy with

brown skin and white flesh color. Key traits: dwarf and bushy suitable for close spacing (60cm x 60cm).

Sree Swetha-1

It is a hybrid (Dr375 x Sree Dhanya) with 9months duration. It has an average yield of 30 t ha and potential -1

yield of 40 t ha . It has medium starch content of 22.02% and 3.8% protein. It is dwarf, bushy, non climber of

30-50 cm height. Emerging leaves are dark green and narrow mature leaves with light green petiole. Tubers

are cylindrical with brown skin and white flesh color. Key traits: dwarf and bushy suitable for close spacing

(60cm x 60cm).

Sree Haritha-1It is a hybrid (DrH42 x DrH314) with 9-10 months duration. It has an average yield of 46 t ha and potential

-1yield of 60 t ha . It has medium starch content of 24.02% and crude protein content of 3.2%. It is a climber

twining to right with spiny green vine. Emerging leaves are green and mature leaves are dark glossy unifoliate

with wavy margin. Tubers are compact and cylindrical with brown skin and white flesh color. Key traits:

Excellent cooking quality with good flavor and drought tolerance.

2.1.3 White Yam (Dioscorea esculenta)

Sree Latha

Released in 1983 as a clonal selection from indigenous germplasm with 8 months duration. It has an average -1 -1

yield of 25t ha and potential yield of 35 t ha . It has low starch content of 18-19% and medium crude

protein content of 2.0 -2.5%. It is a climber twining to left with spiny dark brown vine. Emerging leaves are

light green and mature leaves are cordate with brownish green petiole. Tubers are oblong to fusiform with

grayish brown skin and creamy white flesh color. Key traits: Excellent cooking quality.


Sree Kala

Released in 1993 as a clonal selection from exotic germplasm with 7- 8 months duration. It has an -1 -1

averageyield of 20t ha and potential yield of 36 t ha . It has medium starch content of 23-25%. It is a

climber twining to left with spiny dark brown vine. Emerging leaves are light green and mature leaves are

cordate with brownish green petiole. Tubers are oblong to fusiform with grayish brown skin and creamy

white flesh color. Key traits: Excellent cooking quality.

3. Edible Aroids varieties released by ICAR-CTCRI

3.1 Elephant foot Yam

Elephant foot Yam (Amorphophallus paeoniifolius(Dennst.)) is a herbaceous diplod (2n=2x =26,28)

species of Araceae grown across Asia and Australia for leaves as well as corms. It has wide adaptation to

different ecological conditions and has high productivity (Santosa et al.2017).


l High and stable tuber yield


l Resistance to biotic stresses (collar rot)



l Low acridity

Gajendra

Released in 1991 as a selection from local collections of Kovvur, West Godavari District with 180-210 days -1 -1

duration. It has an average yield of 42 t ha and potential yield of 55 t ha . It is medium tall (78cm), with

medium canopy spread, white petiole with green ornamentation. Tubers have brown skin color and yellow

with orange tinge flesh color. Key traits: fairly tolerant to leaf blight, No major pests and moderately tolerant

to drought and flood. Suitable for all conditions and responds well to high input agriculture.

Sree Padma

Released in 1998 as a selection from indigenous germplasm collection from Wayanad (Kerala) with 8-9 -1 -1months duration. It has an average yield of 42 t ha and potential yield of 80.2 t ha . It is medium tall (78cm),

with medium canopy spread, light green petiole with green ornamentation. Corm shape is globose and tubers

have brown skin colour and cream flesh color. Key traits: Excellent cooking quality.

Sree Athira

Released in 2006 as a hybrid selection from Am -15 x Am -45 with 9-10 months duration. It has an average -1 -1yield of 40.5 t ha and potential yield of 45.6 t ha . It is medium tall (85-110 cm), with medium canopy

spread, light green petiole with green ornamentation. Corm shape is globose and tubers have brown skin color

and pink flesh color. Key traits: Excellent cooking quality, tolerant to collar rot and mosaic disease.

3.2 Taro

Taro (2n=2x=28,42) is a herbaceous perennial belonging to genus colocasia and family Aaraceae. Colocasia

esculenta var esculenta and Colocasia esculenta var antiquorum are the most commonly cultivated species

of taro. The wild forms of taro are not used for consumption because of high acridity (Banjaw et al.2017)



l High and stable corm yield

l Wider adaptability


l Resistance to biotic stresses (taro leaf blight and dasheen mosaic virus)



l Low acridity

Taro varieties released by ICAR-CTCRI

Sree Rashmi-1

Released in 1987 as a selection from germplasm with 7 months duration. It has an average yield of 18 t ha -1

and potential yield of 32.0 t ha . It is erect and tall with drooping leaves having straight margins. The color of

the petiole with green at top and purple at base and middle. Corm shape is cylindrical and big and cormels are

conical. Tubers have brown skin colour and white flesh color. Key traits: Good cooking quality

Sree Pallavi

Released in 1987 as a selection from germplasm collection from Meghalaya with 7 months duration. It has an -1 -1

average yield of 16 t ha and potential yield of 18.0 t ha . It is erect and tall with drooping leaves having

green margin and petiole. Corm shape is conical and big and cormels are small and club shaped. Tubers have

brown skin color and white flesh color. Key traits: Good cooking quality, field tolerant to Leaf Blight and

dasheen mosaic virus.

Bidhan Chaithanya

Released in 2000 from AICRP on Tuber crops, Kalyani Centre, West Bengal with 160-170 days duration. It -1 -1

has an average yield of 15-20t ha and potential yield of 25-30 t ha . It is erect and tall with drooping leaves,

waxy and blunt tips. It has green petiole and oval corm shape. Tubers have white and brown skin color with

white flesh color. Key traits: Good cooking quality, no-irritant, good for chips making (dry matter content:

24%)

Muktakeshi

Released in 2002 as a clonal selection from Bhatpara Village, Cuttack, Odisha with 150-180 days duration. -1 -1

It has an average yield of 20 t ha and potential yield of 30 t ha . It is erect and tall with medium tillering,

narrow leaves with green petiole. Corm is round and cormel is cylindrical. Tubers have light grey skin color

and white flesh color. Key traits: Good cooking quality, non acrid, resistant to Leaf Blight and field tolerant to

dasheen mosaic virus, aphids, cut worm and scale insects and is suitable for upland and lowland cultivation.

Sree Kiran -1It is the first taro hybrid released in 2004 with 190-210 days duration. It has an average yield of 17.5 t ha and

-1potential yield of 28.5 t ha . It is semi erect, medium tall with broad and droopy leaves with purple margin and

greenish brown petiole. Corm is oval and cormel is round to oval. Tubers have light brown skin color and

white flesh color. Key traits: Good cooking quality and prolonged shelf life.

Pani saru-1-1It is a local landrace released in 2005 with 6-7 months duration. It has an average yield of 15.7 t ha and


-1potential yield of 20.2 t ha . It is erect, tall with erect leaves and green petiole. Corm is round and cormel is

elliptical. Tubers have light brown skin color and white flesh color. Key traits: Good cooking quality and

prolonged shelf life. Suitable for water logged/submerged condition.

Pani saru -2

It is a local landrace from Begunai, Odisha released in 2005 with 6-7 months duration. It has an average yield -1 -1of 13.0 t ha and potential yield of 18.0 t ha . It is medium tall with erect leaves and green petiole. Corm is

round and cormel is round to elliptical. Tubers have light brown skin color and white flesh color. Key traits:

Good cooking quality, field tolerant to leaf blight and suitable for water logged/submerged condition.

Bhu Kripa

A selection from local landrace Jhankri, Bhu Kripa was released in 2017 with 6-7 months duration. It has an -1average yield of 15.0-20.0 t ha . It is erect,medium tillering with cup shaped leaves and green petiole.

Corm is round and cormel is round. Tubers have brown skin color and white flesh color. Key traits: non acrid,

excellent cooking quality, biotic and abiotic stress tolerant.

Bhu KripaBhu Sree

A selection from local landrace Sonajuli, Bhu Sree was released in 2017 with 6-7 months duration. It has an average -1yield of 15.0-20.0 t ha . It is erect, medium tillering with broad leaves and green petiole. Flowering is profuse. Corm is

round and cormel is elliptical. Tubers have light brown skin color and white flesh color. Key traits: good cooking

quality, biotic and abiotic stress tolerant.

Bhu SreeBunda

Narendra Bunda

Released in 1999 from AICRP on Tuber crops, NDUAT, Faizabad, Uttar Pradesh with 180-195 days duration. It has an -1 -1

average yield of 38t ha and potential yield of 42 t ha . It is erect and tall with erect leaves, purple-green petiole,

cylindrical and medium sized corm with elliptical cormel. Key traits: shelf life 4-5 months, less acrid, soft and easy

to cook


References

1. Dejene Taddesse Banjaw. 2017. Review of Taro (Colocasia esculenta L.) Genetics and Breeding. J. Hortic., 4:1.

2. Hijmans, R., Huaccho, L. and Zhang, D. 2002. Description and analysis of a geo-referenced database of the global

distribution of sweet potato area. In: Proceedings of First International Conference on Sweet Potato. Food and

Health for the Future, Lima, Peru. Acta Horticulturae, 583: 41-49.

3. Mukherjee A., Sheela M.N., Asha K.I., A.A.Devi, Shirly Raichal Anil, Krishna Radhika N. and Senthilkumar K.M.

2019. Tuber crops varieties released by ICAR-CTCRI.2019, Technical Bulletin No.77, ICAR-Central Tuber Crops

Research Institute, Thiruvannthapuram, Kerala.

4. Santosa, E., Lian, C.L., Sugiyama, N., Misra R.S., Boonkorkaew, P. and Thanomchit, K. 2017. Population structure

of elephant foot yams (Amorphophallus paeoniifolius (Dennst.) Nicolson) in Asia. PLoS ONE, 12(6): e0180000.

5. Sunitha, S., James George, Sheela, M.N., Suresh Kumar J. and Archana Mukherjee. 2018. Tuber crops varieties

released/recommended for release by AICRP on tuber crops over five decades, Technical bulletin no.71, ICAR-All

India Coordinated Project on Tuber Crops, ICAR-CTCRI, Thiruvananthapuram, Kerala, India, 140 p.


Most of the world's poorest smallholders in the developing tropics depend on root and tuber crops as their

principal source of food and nutrition. These species produce large quantities of dietary energy and have stable

yields under difficult environmental conditions. The most important crops are cassava, sweet potato, yam and

the aroids, sharing important common traits such as bulkiness, post-harvest perishability and vegetative

propagation. Unlike cereals, pulses or other commercial crops, planting material production techniques were

non-existent in tuber crops. Further, these crops are vegetatively propagated and have a low multiplication ratio

with regard to planting material production. However, in the recent past, economic importance of these crops

has risen up considerably and therefore the demand for quality planting material has also increased. Lack of

availability of healthy and improved planting materials is a major handicap faced by tuber crop farmers. Since

tuber crops are clonally propagated, spread of disease becomes very easy. Another serious problem is the poor

multiplication ratio in these crops unlike cereals and pulses. While in cereals the multiplication ratio is as high as

1:140, in cassava it is 1:10, Amorphophallus it is 1:3, in yams it is 1:4 and in colocasia the multiplication ratio is

1:20. This low multiplication ratio is mainly responsible for the undue delay for the released high yielding

varieties to reach the farmers. Minisett technique developed at CTCRI is an effective and viable technology

which is farmer friendly and has since then proved to be quite effective in rapidly producing quality planting

materials in tuber crops. The minisett techniques in major tuber crops are briefly presented here.

CASSAVA (Manihot esculenta Crantz)

Cassava (Manihot esculenta Crantz.) commonly known as tapioca in India is a staple food of more than 300

million people and also serves as an important raw material for several industries. Its importance in tropical

agriculture is due to its drought tolerance, wide flexibility to adverse soil, nutrient and management conditions

including time of planting since the crop is photo insensitive. The drought tolerance is mainly due to the inbuilt

mechanism to shed the leaves under adverse soil moisture conditions to facilitate slow down of all the vital

activities of the plant. Hence cassava is a versatile crop that can grow and yield under unfavourable conditions

where most of other crops would fail. Apart from its role as a staple/subsidiary food, during the past few

decades there has been growing recognition of the value of cassava roots as a low cost energy source for

livestock and as a raw material for industrial starch and fuel alcohol.

In traditional system of planting, cassava setts of 20 cm length with 10 to 12 buds are used as planting material.

However, out of the 10 or 12 buds only two are allowed to sprout and then retained, while the rest are discarded

and hence wasted. By minisett technique it is possible to utilize the capability of every bud to sprout and grow as

a new plant and thus enhance the multiplication ratio. It is based on the concept that once the bud sprouts, the

roots developed would start drawing nutrients from the soil and no more from the mother planting material and

therefore the size of planting material actually does not matter as far as sprouting is concerned.

Preparation of Minisetts

For producing minisetts, first step is selection of mature, disease free stems (preferably those obtained from

meristem culture). In a study conducted at CTCRI to standardise the optimum size of minisett planting material

in cassava, three sizes of nodal cuttings: single node, two node and three nodes were tested. Single node cutting

was significantly inferior and the two node and three node minisetts were on par for all growth and yield

PLANTING MATERIAL PRODUCTION TECHNIQUES IN TROPICAL TUBER CROPS

J. Suresh KumarAICRP-TC, ICAR-Central Tuber Crops Research Institute, Sreekaryam, Thiruvanathapuram, Kerala, India


parameters. Hence,two node minisetts has been standardized as the optimum size for rapid production of

planting materials in cassava.

Minisetts are prepared from healthy stems using a sharp hack saw. Top one-third portion is usually discarded in

the traditional system, however in minisett technique, the whole stem is used. When tip cuttings are taken, it is

advisable to place them in water so as to prevent dehydration. The stem just below the growing tip is very tender

with prominent axillary buds. Hence from this portion, cuttings with four nodes are taken instead of two as the

latter may dry up very fast. Sufficient care should be taken such that no damage is caused to the axillary buds.

The woody stock at the base is discarded. About 50 to 70 minisetts could be prepared from a stem.

Shade-net house

Since the minisetts ought to be free of any diseases and pests, it is essential to raise them in a protected

environment. A shade net house of 30 x 7 m dimension would be ideal. Net of 35 % shade is proved to be ideal.

The roof as well as sides of the net house should be totally covered so as to ensure protection from insects and

pests.

Preparation of nursery

Prior to making beds, it is desirable to dig the soil well, break clods and form fine tilth. To set the beds, mark out

convenient length and the width should be invariably 1 m. The width of the nursery bed should be selected in

such a way that the middle portion of the bed should be easily reachable from either side. Make raised beds (20

cm height) of soil and sand, mixed in the ratio of 50:50. It is advisable to line the sides of the bed with cement 2

hollow bricks, so hat the soil remains in place, despite irrigation and nursery operations. A nursery area of 45 m 2is required for producing minisetts for planting one hectare of land, or 18 m of nursery area for planting 1 acre.

Planting minisetts in nursery

Furrows are made across the width of the bed with a khurpi or small hand hoe, about 5 cm deep. Two node

cuttings are then planted in the furrow, end to end horizontally, with the buds facing either side. A spacing of five

cm is could be provided between two rows. Minisetts planted in the furrow is then covered with a fine layer of

soil: sand mixture.

Tip portion minisetts and four node minisetts from the top tender portion of the stem must be planted vertically

in the nursery rather than in horizontal position. This is because the chances of the tender minisetts getting

decayed due to excess moisture are very high, if horizontally embedded in the soil. When vertically planted, a

spacing of 5 x 5 cm could be adopted for facilitating growth of the minisetts.

Nursery management of minisetts

Light irrigation is given soon after planting and then another could be given after four or five hours. From the

next day onwards, intermittent irrigations could be given for about two weeks. Irrigation could be provided

through a net work of micro sprinklers fitted on 3/4" PVC pipes, connected to a water tap. The minisetts would

start sprouting in a week's time. Chemical fertilizers should not be applied. It is advisable to spray Dimethoate

(0.05 %) at fortnightly interval as a prophylactic measure against pests like white fly which is responsible for

spreading cassava mosaic disease (CMD). Routine examination of minisett nursery is essential to detect

incidence of CMD and if an infected minisett is found, it should be immediately pulled out and destroyed.

Transplanting minisetts to main field

The minisetts will be ready for transplanting in about three to four weeks time. Minisett having two to three fully

opened leaves is the optimum for transplanting. Prior to uprooting, the main field should be properly prepared. It


-1should be thoroughly ploughed and brought to a fine tilth. About 12.5 t ha of dry FYM is spread in the field.

Ridges of 30 cm height are taken with a spacing of 45 cm between the ridges. Uprooting minisetts from nursery

beds could be done with the help of a khurpi, taking maximum possible care not to break roots.

Uprooted minisetts are then carefully planted on ridges at a spacing of 45 cm. On an average, about 50,000

minisetts could be transplanted in one hectare of land. Availability of moisture in the field must be ensured till

the transplanted minisetts are established. So It is very essential that the transplanting of minisetts must

coincide with rainfall, if the crop is to be raised as a rainfed crop. If it is a dry period, proper irrigation must be

assured.

Management of transplanted minisetts-1

The transplanted minisetts usually gets established in a week's time. After establishment, 50:50:50 kg ha of N,

P and K may be applied as basal and one month later, the second dose of fertilizers, 50:50 kg each of N and K

per ha may be applied as top dressing. Weeding and intercultural operations could be done at the application of

second dose of fertilizers. The plants would mature in about 7 – 9 months time depending upon the varietal

character.

Harvest

On harvest from a hectare about 60,000 cassava stems and 75 to 80 tons of tubers could be obtained by adopting -1minisett technique, whereas, in the traditional production system, about 24,000 stems and 30 t ha of tubers

could be obtained. If minisett technique is adopted for further multiplication, then minisetts for planting 50 - 60

ha could be obtained in the next generation. Multiplication ratio in cassava planting material by this process is

enhanced to 1:70 from the traditional 1:10.

Storage of planting materials

Stems produced through minisett technique should be stored in a well ventilated store house facilitating diffused

light inside the shed. Harvested stems should be kept erect and never horizontal on the floor. The stems could be

kept vertical by providing a support structure inside the storage shed. Stems stored thus remains viable for about

three months. Stems can also be stored vertically under the shade of a tree or under a shade roof. Studies have

also revealed that the stems can be safely stored for over three months in “zero energy cool chambers”.

YAMS (Dioscorea spp.)

Yams (Dioscorea spp.) are grown in India since very ancient times and D. alata is said to be of Indian origin.

Dioscorea rotundata is a native of West Africa while D.esculenta could be of Burma or Indo-China in origin.

Yams hold an enviable position as a staple food crop as well as a cash crop in Western Africa, especially in

Nigeria. It is a rich source of carbohydrates, certain vitamins and has high calorific value. Starch constitutes the

predominant carbohydrate component in most of the species of yams, the range being 11 – 39% and protein

content in the range, 6 – 13 % on dry weight basis. Though yams are cultivated in every tropical country, their

large scale cultivation is restricted mainly to West Africa, South–East Asia including China, Japan and Oceania

and the Caribbean. In India, yams are cultivated mostly in Southern and North Eastern States. White yam or

Dioscorea rotundata is a recent introduction to India and is gaining lot of popularity due its culinary qualities.

Planting material of yam

Yam is propagated vegetatively and whole tuber is the ideal source of planting material. Traditionally yam is

cultivated by making setts of 250 g from mother seed yam. These are planted in mounds formed over pits at a


spacing of 90 x 90 cm. From one kg mother seed yam only four setts could be obtained limiting the

multiplication ratio to 1:4. Studies conducted at CTCRI, Thiruvananthapuram have revealed that by reducing

the size of planting material to 30 g, a multiplication ratio of 1:24 could be obtained. Even by reducing the size of

planting material to 30 g misett, the yam still has the capability to sprout because, buds are spread all over the

periderm (body surface) of yam tuber. Yam tuber, by nature has apical dominance; however, when they are cut in

to small size, the dormant buds gets activated and would eventually sprout, subject to the availability of

congenial environment. Hence, any portion of yam tuber is capable of sprouting and producing a new plant.

Further, once the roots are produced from a yam tuber, the physiological system governing the growth of the

crop would prompt the root to draw plant nutrients form the soils and hence no more from the stored food in the

mother seed material.

Preparation of minisetts

For preparing minisetts, the tuber is first cut into small cylindrical pieces of about 5 cm length. From these

cylindrical pieces, minisetts of about 30 g size is prepared. Adequate care should be taken to see that each

minisett has a surface layer of periderm, since minisetts without periderm will not germinate. Treating the

minisetts with any fungicide mixed in cowdung slurry is found to be very beneficial to the crop. Such treated

minisetts should be spread out under shade for a day prior to planting.

Planting in Nursery

Nursery shed of 35 % shade as discussed earlier may be made for raising yam minisetts. Minisetts are planted in

the nursery in furrows made across the bed, 5 cm deep, with cut surface facing up. This helps to prevent drying

up of the periderm. Spacing between two rows is 5 cm. After planting, they must be covered with a thin layer of

soil/sand mixture. Light irrigation soon after planting followed by light intermittent irrigations till sprouting is

preferable. Thereafter, as per need the nursery may be irrigated. The D. alata minisetts sprout within a fortnight

and on reaching three to four leaves stage it becomes ready for transplanting. However, D. rotundata minisetts

are found to take about a month for sprouting. It is therefore essential to time the nursery planting in accordance

with the time of planting in main field.

Transplanting yam minisetts

As mentioned above, transplanting should invariably be done after receipt of rains, on ensuring proper moisture

content in the soil. After field preparation ridges are to be made, 60 cm apart. Sprouted minisetts are pulled out

carefully using khurpi, without damaging the roots and are transplanted on the ridges, 45 cm apart, thus

accommodating about 34,000 plants, while in the conventional planting (90 x 90 cm), only 24,000 plants could

be accommodated in a hectare. The minisetts establish in the field in about a weeks time.

Management of transplanted yam minisetts

Application of well rotten FYM @ 10 t/ha at the time of field preparation is essential. Chemical fertilizers -1

should be applied in the form of NPK @ 100:50:100 t ha . As basal application, 50% of the N and K and full dose

of P could be applied within a week after establishment of the transplanted minisetts. Remaining 50 % of

fertilizers could be applied one month after the application of the first split dose. Along with the fertilizer

application, weeding and earthing up also should be done. It is essential that the vines of yam be trailed since it is

found that trailing of vines enhances tuber yield by about 20 %.

Harvest

Harvest is done with the help of a sharp hoe, taking sufficient care as not to injure the tubers. This is because


bruised tubers cannot be stored as planting material. Tuber size ranging from 300 g to 3.0 kg per plant could be

obtained. By adopting minisett technique, results indicated that the multiplication ratio in yams could be

enhanced to1:24 from the traditional 1:4.

Storage of seed yams

It is advisable to give a healing time to the harvested seed yams prior to their storage, by spreading them under

semi shade condition for a day. This helps in natural healing of all the little wounds on yam tubers so that they do

not get rot while in storage. It is ideal to store yams on a rack, taking care that the tubers do not touch each other.

These racks could be placed in a well ventilated storage shed facilitating diffused light inside. Yams can thus be

stored in viable condition for a period of 3 to 4 months, depending upon the species and variety.

ELEPHANT FOOT YAM (Amorphophallus paeoniifolius)

Among the tuber crops, elephant foot yam (Amorphophallus paeoniifolius) occupies a major position, as a

vegetable crop and also as a cash crop with an year round demand. It is grown widely in tropical and sub-

tropical regions. It is gaining popularity in tropical countries due to its production potential and popularity as a

starchy vegetable having high nutritive and medicinal values.

Planting material in Amorphophallus

Corm setts weighing about 750 g to 1 kg is the conventional size of planting material in EFY. It could be planted

either as cut piece or as whole corm limiting the availability of planting material.. Studies conducted at CTCRI

revealed that by adopting minisett technique, instead of large seed corms, small corm pieces (minisetts) of 100 g

size may be used as the planting material, whereby multiplication ratio could be enhanced to 1:15 from 1: 2.

Preparation of minisetts

In EFY, buds are located in a ring at the center of the corm. So, setts made out of the corm should essentially

have a portion of the central bud, failing which, the sett may not sprout. About 15 minisetts could be made from a

corm weighing 1.5 kg, which may be treated with Trichoderma mixed in cowdung slurry. They are then spread

under shade cover for one day, prior to planting in the main field. This treatment would protect the crop against

attack from Sclerotium rolfsii, a soil borne fungus which causes collar rot.

Planting of minisetts

Unlike cassava or yams, EFY is not planted in the nursery, since studies have shown that transplanted minisetts

of EFY runs the risk of high mortality rate, about 20 to 40. It has therefore been optimized that minisetts could be

planted straight in to the main field for seed production (multiplication). However, planting in nursery bed

simultaneously helps in ensuring a uniform crop stand by transplanting in case of any casuality among the

directly planted minisetts. The field is prepared by thorough digging or ploughing and pits are taken at a spacing

of 60 x 45 cm, instead of the conventional 90x90 cm. A total of 37,000 minisetts could be planted in a hectare of

land while by the traditional method, only 12345

setts would be accommodated in a hectare.

The pits could be of 30 cm deep, and the top soil replaced after mixing it with well rotten cow dung, about 2 kg

per pit along with Titalicize the word, if available. The minisetts are then planted at the center of the pit with the

bud portion facing up. A small layer of soil is packed over the minisetts which are further covered with sufficient

quantity of dry or green mulch. If minisetts are to be transplanted, it should be ensured that sufficient moisture

exists in the field till their establishment so as to prevent drying up. Traditionally Amorphophallus is planted

during February – March. The minisetts will sprout in about two to three weeks. If the seed crop is to be raised


under irrigation, then planting of minisetts could be advanced to make seed materials available for off season

planting.

Filed management

On sprouting, the newly developed roots would start drawing plant nutrients from the soil and not from the

mother seed corm, however, big it might be. Basal application of fertilizers could be done when 50 % percent of -1the planted minisetts sprout. Chemical fertilizers in the form of NPK @ 100:50:100 kg ha was found to be ideal

for the crop. Nitrogen and Potash are applied in two splits, 50 % of the total requirement as basal and the rest as

top dressing, one month later. Phosphate fertilizer could be applied in single dose as basal. Weeding, and

earthing up could be done along with fertilizer application. Drenching of soil at the base of the crop with -1fungicide Bavistin @ 4 g L is advisable against collar rot.

Harvest

The crop would mature in about 8 to 9 months time, indicated by the senescence stage. Harvest is done using

hand hoe or spade, but care should be taken as not to injure the corm, since corm with bruise may easily catch

infection while in storage. Size of the harvested corm from minisetts would be in the range of 600 g to 1.5 kg per -1

plant. Average yield could be expected in the range of 40 to 50 t ha . Multiplication ratio in Amorphophallus

could be thus enhanced to 1:15 from the conventional 1:2 by adopting minisett technique.

Storage

Harvested corms are cleaned and spread out under a shade cover for two days prior to shelving in store, which

helps in healing injuries or bruises on the corm. The corm could be safely stored on racks in a well ventilated

store house facilitating diffused light. While placing on racks, it is advisable to keep them without touching one

another. Amorphophallus could be stored this way in viable condition for a period of three months. Storing EFY

in zero energy cool chambers has been standardized at ARS, Kovvur, whereby corms could be safely stored for

three to four months without loosing viability.

TARO (Colocasia esculenta) & TANNIA (Xanthosoma sagittifolium)

Both taro and tannia are very popular crops in Aroids. They are cultivated as a vegetable crop in India, Burma,

China, Hawaii, Fiji and many south East Asian countries. Taro also finds a place as a popular tuber crop in Egypt,

Africa and Caribbean. In India both taro and tannia are very popular in most of the States, especially in Kerala,

Tamil Nadu, A.P., Orissa, West Bengal, Assam etc. It has very good nutritive values and form a rich source of

calcium, iron, phosphorous, vitamin A and C.

Planting material

Cormels as well as mother corms are used as planting materials, however, cormels are found to be ideal as

planting materials. Conventionally, cormels weighing 20 to 25 g are used as planting material in taro while in

tannia about 60 g size is used as planting material. Studies conducted at CTCRI have revealed that the

multiplication ratio in these crops can be significantly enhanced by adopting minisett technique. Raising

minisetts in nursery is not required in these crops, since they get easily established while planting straight in the

prepared field, provided there is availability of sufficient moisture. However, nursery could be raised in places

of scarce rainfall, and under such condition, it may be

done in the shade net nursery as specified above.

Production of planting materials

Traditionally farmers set apart a portion of their harvested corms and cormels as planting materials for the next


planting. The viability of taro, however is extremely low (less than a fortnight) however, viability of tannia

planting materials extends to about a month. Both taro and tannia have inherently higher multiplication ratio as

compared to other tuber crops, being 1:20 and 1: 10 respectively. As such, the need for enhanced multiplication

ratio for rapid production of planting materials is comparatively less. However, minisett technique has been

found to be quite useful for quick and large scale production of quality planting materials in these aroids.

Minisett techniques

In minisett technique mother corms are selected from healthy plants at harvest. Such selected mother corms

are first cut in to cylindrical pieces and then cut horizontally into minisetts of about 10 g weight (15 g for

tannia). A major advantage of minisetts in taro and tannia is that the cormels, which are the economic part of

these crops, can be fully marketed since only corms would be required for minisett multiplication. Even if th

cormel is to be used as planting material in taro, only 1/4 of the conventional quantity needs to be stored as

planting material.

Field management

The soil has to be thoroughly ploughed and brought to a fine tilth. The minisetts are then directly planted in the

main field in mounds formed over pits or on raised ridges at a spacing of 45 x 30 cm for taro and 45 x 45 for -1 -1

tannia. Application of FYM @ 12 t ha prior to planting and fertilizers as NPK @ 80:25:100 kg ha is found

effective for the minisetts. N and K should be applied in two equal splits along with the intercultural

operations, the first, soon after sprouting and the second one month later. Mulching is very important and

essential for obtaining higher cormel yield. By adopting minisett technique the multiplication ratio can be

enhanced from 1:20 to 1:120 in taro and from 1:10 to 1: 80

Harvest and storage

Harvesting of taro and tannia is done at the senescence stage of the crop, in about 6 to 8 months time after

planting. On harvest, corms are separated from cormels and are stored separately, spreading out on floor. Care

must be taken to see that the cormels and corms are not heaped on the floor. The harvested materials must be

stored in a well ventilated storage shed, facilitating diffused light.

SUMMARY

Availability of quality planting materials is the most serious constraint in tuber crop production. The situation

becomes worse especially where a part of the economic produce is to be kept as planting material for the next

season. By adopting minisett techniques, the multiplication ratio could be enhanced compared to the

conventional system, thus meeting the demand for healthy planting materials of improved varieties in tuber

crops to a great extent.


Tropical root and tuber crops are well known since ancient times for saving mankind during food crisis. They

play an important role in the dietary habits of people living in the tropics. Tuber crops produce large quantity

of dietary energy and have stable yield under different environmental conditions. The major tropical root and

tuber crops are cassava, sweet potato, taro, bunda, swamp taro, elephant foot yam, giant taro, lesser yam,

greater yam, aerial yam, yam bean, arrow root, coleus etc. Cassava the food-feed-fuel and future crop is

cultivated in Kerala, Tamil Nadu, Andhra Pradesh and Chhattisgarh and in North-Eastern parts of India.

Sweet potato is grown largely in Odisha, West Bengal, Uttar Pradesh, Assam, Bihar, Jharkhand, Madhya

Pradesh, Chhattisgarh, Meghalaya and Maharashtra. Aroids (elephant foot yam and colacasia), yam and

other tuber crops are cultivated in different parts of India. Tuber crops produce high yields in a given time and

space. They can survive in adverse climatic conditions, produce optimum yields; they are insurance crops in

famine and calamity. They are suitable for cultivation in rain fed and irrigated conditions. Suitable for

monocropping, inter cropping with other major crops and forms a component of cropping systems. In India

the area of cultivation of different tuber crops is approximately 400 thousand hectares (t ha). The area of

cultivation of cassava is 173.00 t ha. Sweet potato is produced in the area of 131.0 t ha. Elephant foot yam is in

the area of 30 thousand ha and other minor tuber crops are limited to home or kitchen gardens (NHB 2019).

In propagation of tuber crops the source of planting materials are vegetative plant parts like stem, vine, corms

and cormels, etc. The requirement of planting material is very high in tuber crops like elephant foot yam (6-7 t -1

ha ) and yams, etc which is about 15-20 % of produce from the previous year crop and accounts 20-30 % of

cultivation cost. Hence a novel technique viz; “Minisett technology” has been developed at ICAR-CTCRI.

This overcomes the problem of huge quantity of planting material requirement per unit area of cultivation.

This technique promotes for rapid multiplication of quality planting material of tropical tuber crops.

Major constraints regarding quality planting material production:

l Lack of availability of healthy planting material

l Low multiplication ratio

I. Multiplication ratio of cassava is 1:10 (Means one stem can produce maximum ten plants)

II. Multiplication ratio of elephant foot yam is 1:3

III. Multiplication ratio of yams is 1:4

IV. Multiplication ratio of colocasia/taro is 1:20

l Non availability of commercial seed growers/farms unlike other vegetable seeds, planting materials,

etc.

Minisett technology in cassava:

In traditional system; stems of 20 cm length with 10 to 12 buds are used as planting material in cassava.

However out of the 10 or 12 buds only two are allowed to sprout and then retained, while the rest are discarded

and hence wasted. By minisett technique it is possible to utilize the capability of every bud to sprout and grow

as a new plant and thus enhance the multiplication ratio. It is based on the concept that once the bud sprouts

the roots developed would start drawing nutrients from the soil and no more from the mother planting

RAPID MULTIPLICATION OF QUALITY PLANTING MATERIAL OF TROPICAL TUBER CROPS THROUGH MINISETT TECHNOLOGY

J. Suresh Kumar, S. Sunitha and James GeorgeAICRP-TC, ICAR -Central Tuber Crops Research Institute,Thiruvananthapuram, Kerala,India


The next step is the preparation of nursery. Select a well drained flat site, preferably near a water source for the nursery. Shade net house of 35 % shade is ideal for the germination and growth of minisetts. Mark out the length and breadth and make raised beds of convenient length mixed with fine sand. Dig the soil well, break

2the clods and make raised beds. 145 m nursery area is required for producing minisetts for planting one hectare of land. The width of the nursery bed should be selected in such a way that the middle portion of the bed could be easily reached from either sides. Raised beds of one meter width, ten meter length and twenty centimeter height be ideal. will Two node cuttings are planted end to end horizontally, about five cm deep, with the buds facing either sides. A space of 5 cm is needed between two rows.

Comparison of multiplication ratio:

5 setts

56 setts

Tip cutting 4 node cutting 2 node cutting

Fig: Nursery with raised beds and shade net Fig: Two node cuttings are planted end to end horizontally

Growing tip cuttings and four node top setts should be planted erect at 5 x 5 cm spacing to prevent decay due to

excess moisture content in these tender parts.


Fig: Tips are planted erect at 5 x 5 cm spacing

Irrigating frequently, preferably with micro sprinklers help in early sprouting and proper establishment of the

minisetts. Minisetts would sprout in a week's time. Rouging of cassava mosaic virus infected plants should be

done as soon as such symptoms are expressed, to keep the nursery disease free. Weekly spray of systemic

insecticide to control white flies that transmit cassava mosaic virus is advisable.

Fig: Cassava minisett nursery ready at transplanting stage

Cassava minisetts are ready by 30 days after planting in nursery. Minisetts are carefully uprooted from the

nursery causing least injury to the root and plant. Uprooted minisetts are then carefully planted on ridges.

Fig: Uprooting and planting of minisett in the field for commercial production

A.Minisett technology in elephant foot yam:

In traditional method corm pieces weighing about 750 g to 1.0 kg are useful for planting. It could be planted

either cut piece or whole corm. Use of such large sett size as planting material results in low multiplication

ratio, high cost of planting material, difficulty in transportation, low availability of planting material in

improved varieties. Use of minisetts as planting material has been found to be very effective in solving these

problems, the details are illustrated here:

In minisett technique small corm pieces of 100g weight are used as the planting material. The buds are located

in a ring at the centre of the corm. Setts made out of the corm should essentially have a piece of the central bud

in the minisetts made. Treatment of setts with cow dung slurry and spreading under shade for one or two days

prior to planting is ideal. A total of 37,000 minisetts could be planted in a hectare of land while by the

traditional method only 12,345 setts would be accommodated in a hectare. With minisett technology

multiplication of elephant foot yam could be enhanced to 1:15 from the conventional 1:4.

46

Whole corm Traditional setts Minisett 100 gm

Technical Bulle�n

Minisetts are planted in the pits. The pits size could be 30 cm deep, and the top soil replaced after mixing it with well rotten cow dung, about 1 kg/pit. The minisetts are then planted at the centre of the pit with the bud portion facing up. A small layer of soil is packed over the minisetts which are further covered with sufficient quantity of dry or green mulch. If minisetts are to be transplanted, it should be ensured that sufficient moisture exists in the soil till their establishment so as to prevent drying up.

Whole corm Traditional setts Minisett 100 gm

Fig: Planting in the pits Fig: Field view of the crop from minisetts

B.Minisett technology in yams:

Traditionally yam is cultivated by making setts of 250g from mother seed yam, which limits its multiplication

ratio to 1:6. This low multiplication ratio implies high cost of planting material production, difficulty in

transportation, low availability of quality planting material. Multiplication of mother seed yam by minisetts

has the answer to these problems. By reducing the size of planting material to 30g, a multiplication ratio of

1:24 could be obtained. Buds are spread all over the periderm (skin surface) of yam tuber. Hence any portion

of yam tuber is capable of sprouting and producing a new plant.

For preparing minisetts, the tuber is first cut into small cylindrical pieces of about 5 cm lengths. Adequate care

should be taken to see that each minisett has a surface layer of periderm. Minisett without periderm will not

germinate. Minisetts are planted in the nursery with cut surface facing up, so as to prevent drying up of the

periderm. It is preferable to make the nursery beds in a net house of 35% shade. Spacing recommended

between two rows is 5 cm. Minisett sprout within a fortnight and reaching 3-5 leaf stage, it becomes ready for

planting. sprouted minisetts are pulled carefully without damaging the roots. These minisetts are planted in

the field at 60 X 45 cm spacing preferably on ridges.


Full yam tuber Cut into 4-5 pieces Each piece cut into half

Healthy yam plants Minisett

minisett cutting ready 15DAP

minisett nursery minisett cuttings

Minisett technology in Taro/Colacasia:

This crop inherently has a higher multiplication ratio as compared to other tuber crops, being 1:20. As such

the need for enhanced multiplication ratio for rapid production of colacasia planting material is

comparatively less. However minisett technique has found to be quite useful for quick and large scale

production of quality planting materials. In minisett technique mother corms are selected from healthy plants

at harvest. Such selected mother corms are first cut into cylindrical pieces and then cut horizontally into

minisetts of about 10g weight. Then mlinisetts are directly planted in the field or grown in nursery for about

one month and transplanted into main field. By adopting minisett technique the multiplication ratio can be

enhancing to 1:120 from 1:20.


Conclusion:

In the areas like North Eastern Hill region, remote parts where tuber crops are major staple foods, the major chunk of their produce are used as a propagating material for next season crop could be saved and can be used for consumption with the techniques like this. The advantage of this technique is; it neither requires much skill nor sophisticated equipment for the production of rapid and quality planting material.

References:

1. NHB (National Horticulture Board) 2019. nhb.gov.in/Statistics.asp.


Roots and tuber crops are important cultivated staple energy sources, second to cereals, generally in the tropical regions

of the world. They find an important place in the dietary habits of small and marginal farmers especially in the food

security of tribal population. An important agronomic advantage of root and tuber crops as staple foods is their

adaptability to diverse soil and environmental conditions and a variety of farming systems with minimum agricultural

inputs. Tuber crops in addition to enriching the diet of the people possess medicinal properties that cure many ailments.

Many are used in the preparation of stimulants, tonics, carminatives and expectorants. The ICAR-Central Tuber Crops

Research Institute (CTCRI) is the National Active Germplasm Site for tropical root and tuber crops germplasm in India

and is primarily involved in tropical tuber crops genetic resources management by undertaking activities of germplasm

collection, characterization, evaluation and conservation involving both conventional and biotechnological

approaches. The institute initiated collection of tuber crops germplasm and wild relatives from all over India from 1963

onwards and the germplasm thus collected were characterized, evaluated and conserved.

Management of Genetic Resources of sweet potato

Sweet potato (Ipomoea batatas (L.) Lam.) is an important starchy tuber crop in many parts of the world. It is grown

throughout the tropics and warm temperate regions of the world. It is an important food crop, which is widely grown in

tropical, subtropical and warm temperate regions. Asian countries, particularly China, are the main producers with

113.6 Mt in 2004, representing 88.9% of the world production. The storage roots of sweet potato are used as staple food,

raw material for alcohol production and animal feed. The developing countries alone contribute to 95% of the total

sweet potato production. As per the report of FAOSTAT (2014), the total sweet potato production in the world is

estimated as 106 MT in 8,352,323 hectares. In this, 85.9% of production is from Asia. Others contributions include as

2.3% from Americas, 0.1% from Europe, 0.6% from Oceania and 11.1% from Africa. In India, the average sweet potato

yield is 10.2 t/ha. Sweet potato can adapt to a wide range of environmental condition including soil of poor fertility and

comparatively low pH and also it has a very good drought tolerance capacity. It holds the highest solar energy fixing

capacity among the other food crops mainly due to its enormous capacity to produce dry matter for a long duration.

Sweet potato (Ipomoea batatas (L.) Lam) belongs to the family Convolvulaceae. This crop originated from Central or

South America. Sweet potato is a highly heterozygous crop and has a chromosome number of 2n (6x) = 90, it is

considered to be a natural hexaploid. Sweet potato produced in Asia is mainly used for human consumption and animal

feed and to a limited extend as a raw material for industrial purposes as starch and for alcohol production.

Germplasm is a basic material for breeding, it maintains natural variation of any crop. More than 4,000 accessions of

sweet potato germplasm are maintained in field gene bank as well as in vitro gene bank of International potato center

(CIP), Lima, Peru. The virus indexed accessions are being sent for evaluation to different countries as in vitro material.

In India, sweet potato germplasm is maintained at ICAR-Central Tuber Crops Research Institute (CTCRI). A total of

1400 accessions of sweet potato accession are maintained in the NAGS at ICAR-CTCRI, Sreekariyam and in its

regional station at Bhubaneswar. Collection, Conservation and Characterisation of tuber crops germplasm is one of the

major mandates of the Institute. A lot of variability exists in the leaves, stem and storage root characteristics. A lot of

morphologically similar accessions also exist in the germplasm. It contains many white, orange and purple fleshed

accessions. Field gene bank is mainly for conserving the germplasm, characterization, cataloguing and evaluation of

promising high yielding accessions. In India, so far 35 sweet potato varieties have been released for cultivation, among

them 21 varieties from ICAR-CTCRI, which includes high starch; high β-carotene and high anthocyanin varieties.

In sweet potato, initial cultures were established using meristem or axillary shoot tips. Explants used were from

A HIDDEN TREASURE - SWEET POTATOSanket J. More

Division of Crop Production, ICAR-Central Tuber Crops Research Institute,

Sreekaryam, Thiruvanathapuram, Kerala, India


sprouted tubers or roots as well as those collected from field grown plants. Sweet potato nodal buds were grown in basal

medium without growth regulators. The MS media with varying concentration of Sucrose, Mannitol and growth

regulators viz., NAA, BA and GA3 were used for the standardization of slow growth protocol. Based on the key

morphological characters like plant type, vine colour, leaf shape and emerging leaf colour the accessions showing

morphological similarities were identified and grouped together for duplicate identification. Every year new

germplasm collections are added to germplasm from different parts of India as well as from CIP, Peru for enriching the

germplasm collections in CTCRI.

Why grow sweetpotato?

l Starchy root crop but leaves also be eaten as a leafy green vegetable.

l Leaves are rich source of protein, niacin (vitamin B ), calcium and iron, and a very good source of dietary fibre, 3

vitamin A, vitamin C, thiamine, riboflavin (B ), vitamin B , folate, magnesium, phosphorus, potassium and 2 6

manganese.

l They are especially useful during the dry season when few other fresh vegetables are available.

Apart from staple food, it is a valuable source of extractable starch, slowly gaining a status of a cash crop.

l Poor man’s food → Cash crop

l In many countries it is more often grown as an alternative foodstuff.

l Cultivation area of sweet potato in last decade has expanded faster than any other food crop by over 70%.

It is one of the most suitable crop for value chains and food processing industries.

l No major disease outbreak and tolerant to drought.

l Hidden nutritional treasure: good sources of iron, zinc and potassium, B vitamins and also vitamins K, C and E,

especially high anthocyanin and β-carotene content.

l Most suitable crop for crop diversification, crop rotation and intercropping.

l It is a low input crop that is robust and fast maturing, producing reliable yields even under adverse conditions and on

marginal soils.

l The deep (up to 0.9 m) and branching root system of sweet potato enables the plant to absorb water in deeper soil

layers than occurs in most crops.

l Once roots are established they can survive reduced soil moisture, resuming growth when the rains occur.

It is among the most productive crops with regard to production per unit area and time.

l Unlike a cereal crop, which all has to be harvested at the same time, the roots can be harvested as they are needed by

the farming household (piecemeal/staggered harvesting).

l Greater flexibility: Sweetpotato offers greater flexibility in terms of planting and harvesting times, requires lower

management compared to grain crops and makes less demand on labour.

l Additional benefit: consumed as fresh, dried as hay or made into silage, sweet potato vine is nutritious, highly

digestible and palatable feed for cattle, goats, sheep, pigs and rabbits.

l Healthy alternative: Sweetpotato flour or starch can be used as substitute for helath deteriorant refined wheat flour

in breads, cakes and other bakery products.

l It can contribute towards household and national food and nutrition security, as well as offering the potential for

cash income from sales and creates employment and business opportunities, such as through commercial

production of clean planting material.


Varieties of sweet potato

H 41 Sree Rethna Sree Varun Bhu Sona

H 42 Sree Bhadra Kalinga Bhu Krishna

Varsha Gouri Sree Kanaka Bhu Kanti

Sree Nandhini Sankar Goutam Bhu Ja

Sree Vardhini Sree Arun Sourin Bhu Swami

Best Agronomic Practices for sweet potato

Tuber crops are the second most important group of crop plants after cereals. They are rich sources of starch,

and contain β carotene, antioxidants, dietary fibre, vitamins and minerals. These crops possess high

photosynthetic ability, capacity to yield under poor and marginal soils and tolerate biotic and abiotic stresses.

The Good Agronomic Practices like planting season, method of land preparation, quality planting material,

crop geometry, nutrient management, weed management, water management and proper time of harvesting,

the decisive factors for yield as well as quality are briefly dealt hereafter.

Planting season

Time of planting plays a crucial role in enhancing yield as well as improving quality of tubers. Sweet potato

vines can be planted during June-July under rainfed condition. Under irrigated conditions, planting is usually

done during October-November in uplands and January-February in lowlands (as a summer crop).

Crop Time of planting Planting materialMethod of land

preparation and planting Spacing (cm) N:P:KAverage yield

-1(t ha )

Sweet potato Upland rainfed : June-July Upland irr igated: Oct-N o v L o w l a n d irrigated: Jan-Feb

Vine cuttings

(20-30cm long)

Horizontal /Slant burial; 2-4 nodes below soil on mound/ridge

-1FYM – 5 t ha

60 x 20 cm (Mound)

50:25:50 25-30

Use of quality planting material(40-50% higher yield)

Use of improved and weevil resistantvarieties (15-25% higher yield)

Adoption of better agronomic Practices(60-100% higher yield)

Higher yield


Climatic adaptation

Sweet potato can be grown from sea level up to 2000 m. short days with a low light intensity promote root development

and sweet potato requires a day length of 11.5 hours or less to promote flowering, at 13.5 hours flowering ceases, but

yield do not appear to be affected.

Soil

Sweet potato can be grown on a wide variety of soils but sandy loams reasonably high in organic matter with a

permeable sub soil are ideal. It is acid tolerant crop and yields are usually high in soils with pH of 5.6 to 6.6 (Suja and

More, 2019).

Planting material production

Sweet potato is propagated by means of vine cuttings. To obtain vines cuttings, a nursery is raised either from stored

tuber or from vines of the freshly harvested crop. Vines obtained from nursery are found to be healthy and vigorous

resulting in maximum tuber production. Sweet potato vines are produced by planting good quality tubers 75-150 g in

the primary nursery and multiplied in the secondary nursery for planting to the main field. This necessitates the storage

of good quality tubers for vines production. However, at the time of harvest, a sizeable portion of the harvested tubers

are small or broken and are likely to be rejected in the market. The apical cuttings are found to be the best to secure high

yields from sweet potato. A vine length of 20-40 cm with at least 3-5 nodes is found to be optimum for tuber production

in different parts of India. The cut vines with intact leaves when stored under shade for two days prior to planting in main

field promote better root initiation, early establishment of vines and high tuber yield. The leaves can be removed where

the vines are to be transported to distant places to reduce the bulk. This method can be adopted for multiplication of

planting material which involves transportation costs (Suja and More, 2019).

Land preparation, crop geometry and planting

Soil physical condition influences the plant growth and hence proper soil manipulation and tillage is required for the

successful cultivation of tuber crops. Loosening the soil to a depth of 20-25 cm either by tractor ploughing or spade

digging facilitates better rooting, tuber formation and enlargement. Different methods of land preparation, such as pits,

pit followed by mound, flat bed method, mound method and ridge method are recommended in tuber crops. According

to the situation, different methods are followed. In light textured soils, flat method of land preparation, in heavy textured

soil, mound method and under irrigated condition, ridges and furrow method of land preparation is suggested. Ridge

and furrow method is the widely accepted method of planting for sweet potato. The other common methods of planting

are mounds and flat beds. It is preferable to plant sweet potato on mounds in areas experiencing problems of drainage.

Ridges formed across the slope are recommended in sloppy lands to prevent soil erosion. Usually sweet potato vines are

planted in ridges of 25-30 cm height made 60 cm apart. Vine cuttings are planted at a spacing of 20 cm on ridges (83000 -1plants ha ). Vine cuttings are planted in the soil with both the ends exposed and the middle portion buried in the soil. The

ideal depth of planting is 7-10 cm depth.

Weed management, interculture and after-care

Weeds are also a major constraint in the production of tuber crops, especially under highly erratic rainfall pattern in the

present context of global climate change. Experimental evidences indicate that weeds result in 45-75% yield loss,

besides affecting tuber quality. Intercultural operations are important especially in the early stages of the crop for the

control of weeds and to improve the physical conditions of the soil. Mulching with green or dried leaves immediately

after planting is beneficial for enhancing yield and improving the quality especially in aroids. Once the tuber crops put

forth enough canopy to cover the entire field, weeds do not generally become a problem. Turning of sweet potato vines

restrict the formation of adventitious tuberization in sweet potato.

Nutrient management-1

In trials, carried out at CTCRI, it was found that FYM @ 5 t ha resulted in higher tuber yield. Sweet potato, generally


Crop -1Tuber yield (t ha ) -1Nutrient Uptake (kg ha )

Sweet Potato 18

Ca Mg Zn Cu Fe Mn

22.0 18.0

Name of crop -1Tuber yield (t ha )

-1Nutrient uptake ( kg ha )

Sweet potato 20 123 16 175

N P K

responds to small doses of N application. Excessive N application results in profuse leaf production at the expense of -1root yield. N supply should be moderate, 50 kg ha for optimum tuber production. Application of N, half as basal and

half at 30 days after planting is usually recommended. Trials carried out at CTCRI, indicated that the dose of N can be -1reduced from 50.0 kg to 37.5 kg ha by coating urea with cow dung and inserting into the soil as cow dung ball urea at

the time of planting sweet potato. Trials carried out at Tamil Nadu Agricultural University and Kerala Agricultural

University indicated that application of N half as basal and half as foliar spraying with 2% urea resulted in regulated -1 -1 foliage growth and higher tuber yield .A dose of 25 kg ha P O and 50 kg ha K O is recommended as basal application.2 5 2

Water management: Once a week.

Recent Advances in the Integrated Nutrient Management (INM) in sweet potato

Root and tuber crops (RTC) like cassava, sweet potato, yams, potato, cocoyams and other minor root crops are

important in the agriculture and food security regime of many countries, as it apparently forms a component of the diet

for about 2.2 billion people in addition to contributing to the animal feeds and other industries. The annual world

production of root and tuber crops is about 765 million tonnes (MT) consisting of potatoes (333MT), cassava (237MT),

sweet potatoes (130MT), yams (53MT) and taro and other aroids (12MT) (WCRTC, 2016). The global consumption of

tropical root and tuber crops is around 110 kg/capita/year (CTCRI, 2016). With this global per capita consumption,

these crops occupy a significant place in the food basket of developing nations. Out of the total world production of

RTC, about 45% are consumed as food and the rest being converted as animal feed or industrial products (FAO, 2017).

Why nutrient management is important for tropical tuber crops?

As we know, these crops are recognized as the most efficient converters of solar energy, with cassava and sweet potato -1 -1 -1 -1

producing 250×103 and 240×103 kcal ha d compared to 176×103, 110×103 and 200×103 kcal ha d for rice, wheat

and maize, respectively. This in turn indirectly indicate the quantum of nutrient extraction from the soil to produce dry -1

matter equivalent to this energy. Moreover, rice, wheat and maize when produces yield to the tune of 3-5 t ha , the -1

average per hectare yield from tuber crops ranges as 15-80 t ha further indicating the high nutrient extraction to realize

that much high yield (Table 1). In addition, tuber crops are generally grown in inherently low fertile soils like laterite

soils (Ultisols), red soils (Alfisols) and coastal sandy loam (Entisols) soils which in turn are poor in native fertility, low -1

in cation exchange capacity (CEC) (12-15 me 100 g ) with low organic matter content, low pH, low basic cations

especially K, Ca, Mg, high P fixation, kaolinitic clay nature, lower nutrient retention with very high content of iron and

aluminium oxides particularly in the red and laterite soils. The above facts justify the need to resort to nutrient

management of tropical tuber crops (Susan John K., 2019).

Table 1. Nutrient removal of sweet potato

Table 2. Secondary and micronutrient removal of tropical tuber crops


INM strategies in sweet potato

Liming materials

-1Lime: 2 t ha -1Dolomite: 2 t ha

-1 Gypsum: 2 t ha-1Calcium nitrate: 62.5 kg ha

Soil application of secondary and

micronutrients

Independent application (45 DAP) -1

MgSO : 80 kg ha4

-1ZnSO : 20 kg ha 4

-1Borax: 10 kg ha

At interval of 5-10 days between each application.

Foliar application of secondary and

micronutrients

0.1% Solubor,

0.1% Zn EDTA -15% MgSO4 @ 500-750 g ha

Two sprays at an interval of 20 days during the peak

vegetative growth and two sprays at an interval of 20

days during the tuber bulking

Critical vegetative growth stage of sweet

potato for foliar nutrition

Foliar application of secondary and micronutrients can

be initiated from 2 months after planting (MAP) and can

be continued till 3MAP

1

2

3

4

Ideal harvesting time

Delayed harvesting may result in deterioration of quality, cooking quality and shelf life of the tubers. Sweet potato can be

harvested by 90-120 days.

References

1. CTCRI. 2016. Annual Report, ICAR - Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala, India.

2. FAO. 2017. Statistical Pockets Book of World Food and Agriculture, FAO Statistics Division, Food and Agriculture

Organisation, Rome, pp. 12.

3. FAOSTAT. 2014. Food and agriculture organisation statistical database. [online] Available: http://faostat.fao.org [6 June

2017].

4. Suja, G. and More Sanket J. 2019. Best agronomic practices for tropical tuber crops. In: Training manual on Feed The

Future India Triangular Training (FTF ITT) program on “Integrated Technology for Production, Processing and Value

Addition in Tuber Crops”, 16-30 September, 2019. ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram

695 017, Kerala. pp. 70-78.

5. Suja, G. and More Sanket J. 2019. Sustainable crop diversification involving tropical tuber crops. In: Training manual on

Feed The Future India Triangular Training (FTF ITT) program on “Integrated Technology for Production, Processing and

Value Addition in Tuber Crops”, 16-30 September, 2019. ICAR-Central Tuber Crops Research Institute,

Thiruvananthapuram 695 017, Kerala. pp. 79-91.

6. Susan John K. 2019. Recent Advances in the Integrated Nutrient Management (INM) Practices of Tropical Tuber Crops.

In: Training manual on Feed The Future India Triangular Training (FTF ITT) program on “Integrated Technology for

Production, Processing and Value Addition in Tuber Crops”, 16-30 September, 2019. ICAR-Central Tuber Crops Research

Institute, Thiruvananthapuram 695 017, Kerala. pp. 92-114.

7. WCRTC. 2016. World Congress on Root and Tuber crops, 2016 World Congress on Root and Tuber Crops, Feb 17th to

January 26, Nanning, China.


Tropical tuber crops are grown in tropical zone of the world and consumed as staple foods rich in carbohydrates. These

tubers can grow very well in drought condition and less fertile soil. Tuber crops such as sweet potato, cassava, yam, taro,

elephant foot yam etc. are considered as famine relief crop as well as food security crop. But, these are underutilized and

ignored by researchers its potential to convert to nutritious food products. These are yielded in the form of starchy roots,

rhizomes, tubers, stems and are bundle source of starch (16-24%) but poor in protein (< 4%) and fat (Hoover, 2001).

Apart from starch, tubers also contain health beneficial constituents such as resistant starch (Liu et al., 2006), mucilage

and antioxidant activity (Nagai et al., 2006). The availability of resistant starch in tuber crops makes it suitable for

diabetics due to low in glycemic index. Moreover, these are gluten free in nature and useful in development of gluten

free food products suitable for celiac patients who help to reduce the incidence of this disease (Rekha and Padmaja,

2002). Unfortunately, its consumption and utilization are very limited although it is having good nutrient content due to

perishability, microbial attack, no further processing and no adequate storage which leads to post harvest losses. In

order, to avail the nutritional benefits, it is best to convert raw form to processed form, to prepare different value-added

products which could be beneficial for diabetics and celiac purpose (Aprianita et al., 2009).

Nutritional importance of some potential tuber crops

Tropical tuber crops are merged with the life and food habits of tribal and rural poor. They are rich source of energy as

well as many vitamins and minerals and also possess medicinal values, especially the Dioscoreas, which are exploited

by the tribals. Tuber crops can promote agri-business through the possible value addition and product diversification.

The tribals of Madhya Pradesh, North-Eastern states, Kerala, Orissa etc use tuber crops as staple food. Major

constituent in all tuber crops is carbohydrates (starch), which ranges from 13-30%. Some tubers are good source of

beta-carotene (precursor of vitamin A), anti-oxidants, dietary fibre and minerals and most of them are good sources of

vitamin C but lacks in lipids and protein content. In contrast to tubers, the leaves of tuber crops are very rich in protein.

The leaves are also rich in iron, calcium and vitamins. Most of the tuber crops contain anti-nutritional factors, which

can be effectively removed by resorting to proper processing techniques. The nutritional importance of some potential

tuber crops is explained in detail as follows:

1. Sweet potato

Sweet potato contains natural health promoting component having functional value for the food market, such as β-

carotene, phenolic acids, anthocyanins, carbohydrates, fibers, thiamine, riboflavin, niacin, potassium, zinc, calcium,

iron, vitamins A and C and high quality protein (Grace et al., 2014). It is also a valuable medicinal plant having anti-

cancer, antidiabetic, and anti-inflammatory activities. In the face of being a carbohydrate rich food, sweet potato is also

reported to have low glycemic index (<55), suggesting its suitability as a food for diabetic people (Björck et al., 2000).

There are different varieties of sweet potato such as pale cream coloured, orange fleshed and purple coloured rich in

phenols, β-carotene, anthocyanins etc. The high concentration of stable anthocyanins present in the purple-fleshed

sweet potato tubers and leaves could be an excellent alternative to synthetic colour in food products (Truong and Avula,

2010). This variety is having anthocyanin, phenolics with antioxidant and anti-inflammatory activities (Grace et al.,

2014). These anthocyanins are not only highly stable but also provide health-related radical-scavenging activity,

memory-enhancing effects (Lu et al., 2012), and hepatoprotective activity (Zhang et al., 2013). Orange-fleshed sweet

potato is an excellent source of β-carotene (Grace et al., 2014), responsible for alleviating vitamin A deficiencies and

night blindness (van Jaarsveld et al., 2005).

Sweet potato leaves has not been much used as a human food though rich source of vitamins, minerals and protein.

NUTRITIONAL IMPORTANCE OF TROPICAL TUBER CROPS AND OPPORTUNITY OF PROCESSING IN NE STATES

Namrata A. Giri, M. S. Sajeev and T. Krishnakumar

Division of Crop Utilization, ICAR-CTCRI, Trivandrum-695017, Kerala.


These leaves are used as vegetable in some part of world. It contains high antioxidants particularly phenolic

compounds. This phenolic compound includes caffeocylquinic acid derivatives having antimutagenic effect. Leaves

also attributed high content of lutein to the extent of 29.5mg/100g which has eye protection effect. The nutritional

composition of sweet potato tuber and leaves is presented in Table 1 and 2.

Table 1: Nutritional profile of sweet potato tuber

Parameters Quantity

Dry matter

Starch Amylose content in starch

Sugar (sucrose, glucose, fructose and maltose)

Protein

Dietary fibre

Lipids

Ascorbic acid (Vitamin C)

Total carotenoids

Calcium

Phosphorus

Potassium

Magnesium

13-48%

50-80% of the dry matter 20-28%

6-14% of the dry matter (raw tubers)

Up to 45% in boiled tubers

1 - 7% Sporamin- storage protein (60-80%)

7.0% (dwb) (raw sweet potato roots)

0.29-3%

11-34mg/100g

0.05-14mg/100g

17-45mg

29-57mg

250-450mg

18-36mg

Sr.No

1

2

3

4

5

6

7

8

9

10

11

12

Table 2: Nutritional profile of sweet potato leaves

Parameters QuantitySr.No

22-30% of dry matter

10 mg/100g

27mg/100g

750mg/100g

360mg/100g

60mg/100g

Protein

Iron

Vitamin C

Carotene

Calcium

Phosphorus

1

2

3

4

5

6

2. Cassava

Cassava is known as tapioca, is a dicotyledonous, perennial shrub belonging to the Euphorbiaceae. It is excellent source

of energy and staple food of tropical and subtropical region of the world. Cassavas having the wide applications like

food for direct consumption, animal feed and industrial products. It is also known as food security crop due to it offers

source of income particularly producer. Cassava offers a low cost vegetative propagation with flexibility in harvesting

time and seasons, it has drought resistant root (Haggblade et al., 2012). It was reported that cassava roots could be

stored in the ground for over 2 years, so it is boon for the farmer in West African Countries such as Nigeria (Falade and

Akingbala 2010). Cassava tubers can be processed into various value added products having industrial value such as

flour, alcohol, starches for sizing paper and textiles, sweeteners, biodegradable products. In olden days, cassava was not


Table 3. Nutritional composition of cassava roots and leaves

Proximate composition Cassava roots Cassava leaves

Food energy (kcal) 91

Moisture (g) 45.9 to 85.3 64.8 to 88.6

Dry weight (g) 29.8 to 39.3 19 to 28.3

Protein (g) 0.3 to 3.5

Lipid (g) 0.03 to 0.5 0.2 to 2.9

Carbohydrate, total (g) 25.3 to 35.7 7 to 18.3

Dietary fiber (g) 0.1 to 3.7 0.5 to 10.0

Ash (g) 0.4 to 1.7 0.7 to 4.5

Vitamins

Thiamin (mg) 0.03 to 0.28 0.06 to 0.31

Riboflavin (mg) 0.03 to 0.06 0.21 to 0.74

Niacin (mg) 0.6 to 1.09 1.3 to 2.8

Ascorbic acid (mg) 14.9 to 50 60 to 370

Vitamin A (μg) 5.0 to 35.0 8300 to 11800

Minerals

Calcium (mg) 19 to 176 34 to 708

Phosphorus, total (mg) 6 to 152 27 to 211

Ca/P 1.6 to 5.4 8 2.5

Iron (mg) 0.3 to 14.0 0.4 to 8.3

Potassium (%) 0.25 (0.72) 0.35 (1.23)

Magnesium (%) 0.03 (0.08) 0.12 (0.42)

Copper (ppm) 2.00 (6.00) 3.00 (12.0)

Zinc (ppm) 14.00 (41.00) 71.0 (249.0)

Sodium (ppm) 76.00 (213.00) 51.0 (177.0)

Manganese (ppm) 3.00 (10.00) 72.0 (252.0)

110 - 149

1.0 to 10.0

considered as important crop due to low protein value and high cyanide content, but now it's gaining importance

because it is concentrated source of energy (Falade and Akingbala, 2010) whereas, the high protein content of cassava

leaves and some macronutrients are presents. These tubers are consumed as vegetable in tropical and subtropical

countries (Burns et al. 2012). The cassava roots could be processed into various products having value for industry,

food and animal feed etc. The nutritional value of cassava roots and leaves is given in Table 3.


Table: 4 Nutritional value of the taro corm on a fresh weight basis

3. Taro Taro (Colocasia esculenta) is an extensively cultivated root crop of the tropical areas like South East Asia, the Pacific

Islands, Africa, the United States of America and the Mediterranean. It is also widely cultivated and utilized in the

North-east states of India. Taro corms contain very less amount of fat and protein but it is excellent source of

carbohydrates (90.8-95.5%) and minerals such as magnesium (32.9-382 mg/100g), calcium (25.4-192 mg/100g) and

potassium (3.5-59.7 mg/100g) (Kaur et al., 2011; Njintang et al., 2011). Besides its nutritional importance, it also

contains high level of gum, which helps to reduce blood pressure, hypercholesterolemia and diabetes (Njintang et al.,

2011). Although taro constitutes up to 16% of the total calorie intake in Polynesia, its value addition is meager. Taro is

reported to be rich in mucilage, which has hypocholesterolaemic and hypoglycemic effects (Njintang et al., 2011).

Njintang et al., (2008) examined potential of taro flour for bread and biscuits making and found that up to 10% level, it

did not alter the wheat dough alveography. Himeda et al. (2014) reported that use of wheat-taro composite mixes in

biscuits making and reported that up to 10-15% substitution level was acceptable. Taro is easy to digest due to micro

size of starch grain, and its hypoallergenic behavior responsible for its uniqueness. Taro corms are used as ingredient for

preparation of weaning food and food for elder ones due to its digestibility (98.5%). The composition of taro corm and

leaves is presented in Table 4 and 5.

Moisture 63–85 %

Carbohydrate (mostly starch) 13–29 %

Protein 1.4–3.0 %

Fat 0.16–0.36 %

Crude fiber 0.60–1.18 %

Ash 0.60–1.3 %

Vitamin C 7–9 mg/100 g

Thiamine 0.18 mg/100 g

Riboflavin 0.04 mg/100 g

Niacin 0.9 mg/100 g

Component Content

1

2

3

4

5

6

7

8

9

10

Sr.No.

Table 5: Nutritional composition of taro leaves

Sr.No. Parameters Quantity/100g fresh weight

Protein 3.9-7.0g

Calcium 225-460mg

Phosphorus 82-125mg

Carotene 10-12mg

Riboflavin 0.26-0.45mg

Vitamin C 12.63mg

1

2

3

4

5

6


4. Elephant Foot Yam

Elephant foot yam belongs to Araceae family and major important crop of tropical and sub tropical countries due to its

nutritive value (Ravindran and George, 2008). Elephant foot yam is broadly cultivated and consumed in south eastern

countries like India, Philippines, Malaysia, Indonesia. It is consider as economic crop particularly in India because of

its high production potential, market acceptability and lucrative economic returns (Misra et al. 2002). In India, it is

major crop of Andhra Pradesh, West Bengal, Gujarat, Kerala, Tamil Nadu, Maharashtra, Uttar Pradesh, and Jharkhand.

Table 6 represents the nutritional composition of elephant foot yam tuber. The presence of anti-oxidant vitamins such as

Vitamin C and Vitamin E enhance the health value of Elephant foot yam tubers. The tubers are especially rich in Zinc

containing 2.0-2.3 mg/100 g as against a recommended dietary intake of 0.015 mg. As per the reports, Zinc is an

important component of more than 300 enzymes in the human body that participate in the synthesis and catabolism of

carbohydrates, lipids, proteins and nucleic acids. Zinc also plays a vital role in immune system and is associated with

cellular and humoral immunity. Elephant foot yam tubers contain flavonoids and tannins contributing to health effects.

Quercetin was a major flavonoid isolated and characterized from Elephant foot yam, which has reported anti-oxidant

activity.

Table 6: Nutritional composition of elephant foot yam tuber

Sr.No. Parameters

Major nutrients (g/100g dwb)

Carbohydrates 70.75

Protein 11.53

Fat 3.52

Content

Crude fibre 14.32

Ash 6.90

Minor nutrients (mg/100g dwb)

Potassium 3.81

Zinc 2.31

Iron 34.0210

1

2

3

4

5

6

7

8

9

5. Yams (Dioscorea spp.)

Yams are sources of essential micro-nutrients and phytochemical compounds. Some of nutritional significant

phytochemicals in yams are iron, zinc, ascorbic acid, pro-vitamin A carotenoids, polyphenols and flavonoids.

Mucilages are bioactive natural products which possess many activities such as anti-tumour, anti-inflammatory, and

immuno-modulatory and anti-oxidation. Several physiological effects including lowering of lipid and sugar levels in

blood, antioxidant activity, anti-mutagenic activity and anti-allergic activity have been reported in yam extracts due to

the presence of phenolic phytochemicals. Wide variation exists in the colour of the tubers, contributed mainly by the

bioactive pigments.

Some varieties of yam are highly coloured, especially D. cayenensis, called yellow yam. The colour of yellow yam is

because of carotenoids, consisting mainly of beta-carotene. Purple fleshed cultivars contain anthocyanins, which are

antioxidants. The nutritional profile of yam tuber is mentioned in Table 7.


Table 7: Nutritional profile of yams

Dry matter content 32-44%

Starch 51-90% of dry matter

Mucilage (glucoproteins) 2.5% in D.esculenta

1.4% in D.alata

2% in D. rotundata

lipid content 0.12-1%

Protein content (Major amino acid is arginine) 3.5-7% on dry wt. basis

Dietary fibre 1.2 to 2.3%

Sr.No. Parameters Content

1

2

3

4

5

6

Processing of tubers into value added food products

Tuber crops are perishable in nature and could not store for longer time after harvesting. The high

moisture content led to microbial spoilage of tubers. The processing of tubers to different value added

products in order to extent shelf life and add value to the products. Tubers could be processed into different

primary products such as flour, chips, puree etc and secondary products like biscuits, pasta, noodles etc.

Processing opportunities in North Eastern states of India

The north eastern region is considered to be the richest reservoir of genetic variability of tuber crops

i.e. colocasia, dioscorea, cassava, sweet potato etc. These crops are an integral part of dietary system of

tribals of the region and are grown abundantly in their jhum land or kitchen garden as mixed cropping. The

considerable diversity has been reported in several states like Arunachal Pradesh, Assam, Manipur,

Meghalaya, Mizoram, Nagaland and Tripura. Alocasia occurs in wild in humid tracts being more common.

The region's comparative advantages in producing tuber crops can be tapped by setting up small-

scale processing units for the local market which will also boost rural employment. This set-up is

economically viable as well as doable as a small processing unit requires little capital. In order to benefit

from the cross border trade initiatives industries in the region need to develop goods to be exported to the

neighbouring countries. Processing industries have to be set up to manufacture quality goods, which can be

offered in international markets at acceptable prices. ( )www.pwc.com/in

Tuber crops available in the north Eastern region are not being exploited properly, but they have the

potential to alleviate the poverty, food and nutritional security through processing, value addition and

diverse use. These are rich in vitamins and minerals. Moreover, these underutilized crops are having the

capability of growing in adverse environmental conditions. However, these crops are not grown

commercially and confined either in backyard garden or in the forest.

Potential underutilized tuber crops for value addition

Underutilized tuber crops can be exploited for processing as most of them are rich in nutritive and

medicinal values, but are highly perishable in nature. These tuber crops can be processed into fried chips,

powder, French fries, minimally processed products, boiled/steamed/baked tubers, candy, jam, jelly, RTS

beverages, fried snack products, bakery products, pasta, noodles, instant products etc. The value addition of

tuber crops to different products is summarized in Table 8.


http://www.pwc.com/in

Table: 8 value added products from tuber crops

Name of tubers Value added products

Cassava

Fried chips, French fries, dried chips, high quality flour,

fried snacks, boiled/steamed/baked tuber, vegetable curry,

porridge, pickle, pasta, noodles, candy, biscuits, cookies,

cake, bread, papad etc.

Sweet potato

Fried chips, dried chips, flour, boiled/steamed/baked

tuber, vegetable curry, pasta, noodles, candy, biscuits,

cookies, cake, bread, jam, jelly, wine, curd, pickle, RTS

beverages, instant mix for porridge, gulab jamun mix etc.

TaroFried chips, flour, boiled/steamed/baked tuber, vegetable

curry, biscuits, cookies, pasta, noodles etc.

Elephant foot yamFried chips, flour, boiled/steamed/baked tuber, vegetable

curry, papad etc.

Yam Boiled/steamed/baked tuber, vegetable curry, chips, flour,

candy, chocolate balls, biscuits, cookies, cake, snack

products, pasta, noodles etc.

Sr.No.

1

2

3

4

5

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