Belum VS Reddy, A Ashok Kumar, P Parthasarathy Rao and P Sanjana Reddy

International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Patancheru 502 324, Andhra Pradesh, India

Global Consultation on Pro-poor Sweet Sorghum Development for Bioethanol Production and Introduction to Tropical Sugar Beet Agenda, 8-9 Nov 2007, Rome

Sweet sorghum domains, hybrid sweet sorghum seed production

and agronomic practices: An overview

Contents

SAT and hungry

Sweet sorghum adaptation

Sweet sorghum growing areas/domains

Seed production

Cultivating sweet sorghum

Sweet sorghum vis-a-vis sugarcane

Conclusion

The semi-arid tropics

Mostly located in 48 countries in Asia and SSA

• Inhabited by more than 800 million people: much of the world’s poorest• Unpredictable climate, low/erratic rainfall and poor soils• Inadequate physical and social infrastructure

Near East; North Africa, 39 M

India221 M

Sub-Saharan Africa 204 M

China 142 M

OtherAsia/Pacific156 M

Latin America & Caribbean, 53 M

Where are the hungry?Where are the hungry?

CGIAR Plank 3 - Geographic Priorities: In determining the relative geographic priorities, the CGIAR will give highest priority to developing a concerted approach to address the needs of people in sub-Saharan Africa and South Asia where poverty is concentrated and growing.

Sweet sorghum

• Production similar to grain sorghum

• Sugar-rich stalks (16-23% Brix)

• Ethanol from juice of stalks after fermentation

• Stillage - feed; grain - food

• A cheaper and eco-friendly option for ethanol production

• No sulphur and aldehydes

Temp: 15 to 45oC (optimum 23

to 40oC)

Day length: 10 to 14 hrs

Rainfall 700 to 1500 mm

Relative humidity 15 to 80% 

Sweet sorghum adaptation

Optimum climatic conditions

Red or black loamy with pH 6.5 to 7.5

Organic matter >0.6%  

Depth >80cm

Bulk density <1.4 gcc

Water holding capacity >20% (weight basis)

N = >260 kg ha-1 (available), P = >12 kg ha-1 (available), K = >120 kg ha-1 (available)

Suitable soils

S. No.Particulars of analysis Guidelines followed by ICRISAT

<6.5, acidic6.5 - 8.5, normal>8.7, alkaline<0.8, normal0.8 - 1.6, critical for salt sensitive crops1.6 - 2.5, critical for slat tolerent crops>2.5, injurious to all norms0.5%, low0.5 - 0.75, medium>0.75, high<5.0 ppm, low5.0 -10 ppm, medium> 10 ppm, high<50 ppm, low50-125 ppm, medium125 ppm, high

1 PH (1:2 soil : water)

2Salinity (electrical

conductivity (dS/m)

Reference: Jackson, ML. 1967. Soil chemical analysis.

5Available K (1 N

neutral am. acetate)

3 Organic carbon %

4Available P (Olsen's

method) ppm

Soil critical limits

Soil critical limits (contd…)

S. No.Particulars of analysis Guidelines followed by ICRISAT

<40 ppm, low40-80ppm, medium>80 ppm, high<1000 ppm, low1000-1600 ppm, medium1600-2400 ppm, high

Critical limit ppm8 Zinc (Zn) 0.759 Copper (Cu) 0.50

10 Iron (Fe) 2.0011 Manganese (Mn) 1.00

12Hot water extractable Boron 0.58

13 CaCl2 extractable S 8-10

6Available Mg (1 N neutral am. acetate)

7Available Ca (1 N neutral am. acetate)

For Indian soils DTPA Extractable Particulars

Reference: Jackson, ML. 1967. Soil chemical analysis.

Region 1990-95 2000-05 1990-95 2000-05 1990-95 2000-05

Asia 15.13 11.12 16.90 10.85 1.12 0.98Africa 20.83 23.58 16.47 21.43 0.79 0.91Northern America 3.85 2.93 15.54 11.02 4.04 3.76Others 3.81 4.76 10.55 14.34 2.77 3.01World 43.62 42.39 59.47 57.64 1.36 1.36

Sorghum area, production and productivityArea (m ha) Production (m t) Yield (t ha-1)

Global sorghum statistics

Cultivated over 92 countries in the world.

Period

Area

(m ha)

Production

(m tons)

Productivity

(t ha-1)

Rainy Post- rainy

India Rainy Post -rainy

India Rainy Post -rainy

India

1980-85 10.0 6.2 16.2 8.3 3.3 11.6 0.83 0.53 0.71

1990-95 7.3 5.5 12.8 7.3 3.4 10.7 1.00 0.61 0.83

2000-05 4.4 5.1 9.5 4.6 2.6 7.2 1.05 0.52 0.76

2005-06 3.9 4.8 8.7 5.3 2.3 7.4 1.35 0.48 0.87

Balance sheet of sorghum: India

Source: Agriculture (CMIE), 2005-06 (April 2007)

> 1000 750 to 1000 < 750>25.0 51 12 22 17>7.5 and <25.0 39 19 11 9>2.5 and <7.5 47 24 14 9

Total 137 55 47 35

Rainy season sorghum area 2001-03 - India.Rainfall (mm)Kharif area

(000 ha)No. of

districts

> 1000 750 to 1000 < 750>25.0 24 4 10 10>7.5 and <25.0 19 4 12 3>1.0 and <7.5 16 3 10 3

Total 59 11 32 16

Rabi area (000 ha)

No. of districts

Rainfall (mm)Post rainy season sorghum area 2001-03 - India.

Classes of seed:• Nucleus seed• Breeder seed• Foundation seed• Certified seed

Seed production

Nucleus seed (Basic seed)

Breeder seed (Stage I)

Breeder seed (Stage II)

Foundation seed (Stage I)

Foundation seed (Stage II)

Certified seed(First generation)

Commercial seed

Agricultural universities and Research institutes

-do-

Agricultural universities and seed corporations (public/private)

Seed corporations (public/private)

Farmer

Category Producing agency

Seed-multiplication chain

Insertion of a paper bag onto a pollen-shedding panicle

Anthers from male-fertile (left) and male-sterile (right) panicles

A comparison of developing inflorescences of a male-sterile A-line (left side of each pair) and restorer R-line (right side of each pair) in different growth stages

Nucleus seed production

Variety/R-line

• Self each plant after rouging off types• Plant head to row next generation and rogue

out off types• Self and bulk progenies conferring to the

original description

Initial handful of seed originating through selection/breeding by the breeder

Produced by originating breeder

Steps

Nucleus seed production

A/B-lines• Plant A/B in 2 rows of 1 m

• Rogue out off types/pollen shedders

• Bag before anthesis and make plant to plant crossing between A and B

• Plant the seed of paired A and B, rogue out off types/pollen shedders in A

• Make plant to plant crosses in two/three pairs which confirm to the original description

• Finally bulk within A-line and B-line progeny which confirm to the original line

Breeder seed production

Variety/B-line/R-line• Varieties, B- and R-lines are pure lines• Sown in isolated plot• Maintain >300 m isolation from other sorghum cultivars

for B- and R-lines• >200m from other sorghum cultivars for varieties• >400m from Johnsons grass/other forage/grassy sorghum

types for all types• Crop grown under assured irrigation facilities• Recommended package of practices followed• Rogue out off types before anthesis• Harvest, clean and dry the seeds to <12% moisture

Breeder seed production (contd..)

Male-sterile line• Plant A- and B-line in 4A:2B or 6A:2B ratio• Plant B-line all along the borders• Maintain > 300m isolation from other sorghum cultivars

• >400m from Johnsons grass/other forage/ grassy sorghum types for all types

• Rogue out off types in A- and B- and pollen shedders in A-line before anthesis

• Crop grown under assured irrigation• Recommended package of practices followed• Harvest B-line first followed by A-line• Seed collected on A-line gives rise to A-line• Label the seeds correctly• Harvested B-line seed can be reused for next generation• Clean and dry the seeds to <12% moisture

Foundation seed production

• Intermediate stage between breeder and certified seed production

• Requires certification

• Produced by State Seed Corporations (SSCs)/Central Seed Farms (CSFs)/Extension Agencies (EAs)

• Production supervised by concerned breeders/representatives of SSCs/CSFs/EAs and seed certification agencies

Certified seed

• Last stage of seed production chain• Directly goes to farmers/producers• Produced on large scale by public/private

sectors/EAs/ experienced growers• Quantity produced depends on the demand for

hybrid seed• Requires certification• Production supervised by concerned breeders/

representatives of SSCs/CSFs/EAs and seed

certification agencies

Steps

Varieties• Steps are similar to breeder seed

production• Maintain >100 m isolation from other

sorghum cultivars• >400 m from Johnson grass/other

forage/ grassy sorghum types

Certified seed (contd..)

Hybrids• Production involves A- × R- (hybrid) seed

production• Plant designated A- and R-lines in 4A:2R or

6A:2R ratios in isolated plots• R-lines are planted all along the borders• Maintain >300m isolation from other sorghum

cultivars• >400m from Johnson grass/other forage/grassy

sorghum types• Crop grown under assured irrigation• Recommended package of practices followed

Certified seed (contd..)

• Synchrony in flowering is most important• Staggered planted depending on the difference

in days to flowering between A- and R-lines• Flowering behavior of A- and R-lines interact

with day length and temperature• Staggered planting is standardized for each

seed production area• Careful manipulation of nitrogenous fertilizers

and irrigation improves synchrony of flowering

Certified seed (contd..)

• Rogue out off types, pollen shedders and diseased heads in A-lines before anthesis and off types and diseased heads in R-lines

• Supplementary pollination techniques such as beating R-lines with sticks or brisk walking between R-line rows enhances seed yield of A-lines

• Seed harvested in A-line is hybrid seed that goes to farmers/producers

• Seed collected on R-line is not permitted to be re-used for A x R seed production

• Harvested seed on A-line is cleaned and dried to bring the moisture to <12%

Certified seed (contd..)

Minimum isolation distance required

Minimum isolation distance (m)

Foundation CertifiedField seed field seed field

Other grain sorghum fields 300 200

Field of same variety not 300 25 conforming to varietal purityForage sorghum and Johnson 400 400 grass

An isolated breeders seed production plot of A- and B-lines at ICRISAT

An isolated JKSH 22 hybrid seed production plot at Nandyal , Andhra Pradesh

An isolated breeders seed production plot of S 35 variety at ICRISAT

Maximum permitted level of pollen shedders, off-types, diseased heads for foundation and certified seed

of sorghum

Maximum permitted level (%) Foundation Certified

seed field seed field

Pollen shedders 0.05 0.1Off-types in both seed parent 0.01 0.05 and pollinatorDiseased heads like grain 0.05 0.1 smut and head smut at final inspection

* However, reinspections are allowed after removal of diseased plants before flowering

Projected area of commercial hybrid (ha)

Seed requirement (t)

Area to be sown (ha)

Seed requirement for foundation seed production (kg)

Area to be sown (ha)

Required breeder seed production (kg)

Area to be sown (ha)

100 000 1000 1000 A 6000 6 60 0.1

B 4000 4 40 0.07

R 4000 4 40 0.07

200 000 2000 2000 A 12000 12 120 0.2

B 8000 8 80 0.14

R 8000 8 80 0.14

Estimates of land and seed requirements for various classes of hybrid parents and hybrid seed in sorghum on an

annual basis1

1. A seed rate of 10 kg ha-1

and seed yield of 1000kg ha-1

were assumed for certified and foundation seed plots.

Breeder seed plot yields were estimated on the basis of 600 kg ha-1

.

Certified seed Foundation seed Breeder seed

Planning seed production

Causes of contamination

• Natural crossing with another cultivar

• Mutation

• Unclean harvesting environment

• Carelessness at processing plant

• Mistakes in bagging and tagging

Thorough preparation of fields with the onset of monsoon (summer plowing - apply 10 t ha-1 farmyard manure at last plowing)

Cultivating sweet sorghum Land preparation

Sowing within one week of first shower will help to escape shoot fly damage (aggregated sowings)

Large-scale planting at a time in a given area minimizes shoot fly damage

Agronomic practices

A seed rate of 7.5 to 8.0 kg ha-1

Late sown crop – seed rate of 12-15 kg ha-1

along with Carbofuran 3% G @ 20 kg ha-1

120,000-140,000 plants ha-1

Seed rate/spacing

Sowing

Sowing on ridges with a spacing

of 45 cm between rows and 15

cm within rows or 18“ x 5-6"

3-4 seeds dibbled per hill –

eventually thinned to one per

hill

Sowing with planter is more

appropriate

100 kg N : 50 kg P2O5 and 40 kg

K2O (add potassium especially

on sandy loam soils)

Half N and whole of P and K as basal

Fertilization

Remaining N is top dressed around 35-40 days after sowing

Use 200 kg of Ammonium phosphate (28N:28P:0K) at sowing and apply 100 kg of urea (46% N) at 35-40 days after sowing

Intercultivation and pesticide application

Intercultivation at 15-20 DAS

Observe for shoot fly and stem borer incidence from two weeks after sowing

Furrow application of Carbofuran 3G @2 g/m row at sowing time and spraying endosulfan 35 E.C. 2 ml/l of water at 7th and 14th day after germination controls insect pests

2-3 granules of Carbofuran applied in each whorl at 15-20 days after sowing prevents shoot fly

Protective irrigation if required at Germination

Seedling stage

Flower primordial initiation stage

Flowering

Dough stage of grain formation

Irrigation

Mechanical weeding up to 30 days age of the crop Pre-emergence spray of Atrazine @ 0.5–1.0 kg

ai/ha or stomp (pendimethalin) @ 1.5 kg ai/ha immediately after sowing

Striga management

Crop rotation with trap crops, viz., cotton, sunflower and groundnut

Hand pulling when Striga population is less

Spraying 2,4-D @ 2.0 kg ai/ha

Weed management

Harvesting

Harvest the stalks and grain

separately

Stage – black layer (hilum)

appears at the bottom of the

seed in lower half of the

panicles

Stalks sold to nearby

distilleries within 24 hours

Preparation of cane

Extraction of juice

Major insect pests and management

Affects in the first fortnight of

the crop

Symptoms:

• Drying of central leaf leading to

dead hearts

• Production of side tillers

Shoot fly

Sowing within 7-10 days of the onset of

monsoon (before July 15) avoids shoot fly

Cypermethrin 25%EC @ 0.5 l in 300 l of

water ha-1. 2-3 sprays starting from 6 DAE

(days after emergence) will give effective

control of shoot fly (mix surfactant

"Sandovit" in all the applications @ 1 ml/l)

Shoot fly control

Infests from second week till maturity

Symptoms:• Transparent windows/

shot holes• Deadhearts• Stem tunneling• Peduncle tunneling –

breakage or complete or partial chaffy panicles

Stem borer

Uprooting or burning of stubbles

Endosulfan 35%EC @ 2.0 l in 300 l of water

ha-1 or quinalphos 25%EC @ 2.0 l in 300 l of

water ha-1 or whorl application 5-6 granules

of Carbofuran 3% granules (mix surfactant

"Sandovit" in all the applications @ 1 ml/l)

Stem borer control

Major diseases and management

Grain assumes equal

importance apart from stalk

Caused by a complex of several

fungal species

Symptom:

Grain discoloration depending

on the fungal infection

Grain molds

Leaf diseases

Anthracnose Leaf blight

Rust Downy mildew

Leaf diseases (cont…)

Grain mold Adjusting planting time to escape rain during

grain development Timely harvesting (hilum layer formation) Spraying three times with Captan (0.3%) +

Dithane M-45 (0.3%) at 10 days interval from flowering

Disease control

Leaf diseases

Dithane M 45 (@ 2 g /Liter of water) at 35 DAS

Comparative characteristicssweet sorghum and sugarcane

Parameter Sweet sorghum Sugarcane

Domain Rainfed SAT Irrigated SAT

Propagation Seed Vegetative

Crop duration 4 months 12-16 months

Water requirement 8000 m3 over 2 crops 36000 m3 crop-1

Crop production Mechanized ManualBreeding Hybrid technology Limited hybrids,

based on CMS in breeding restrictedplace to specific

locations

Cost of cultivation 440 over 2 crops 995

(US$ ha-1)

Comparative characteristicssweet sorghum and sugarcane

Parameter Sweet sorghum Sugarcane

Millable stalk (t ha-1) 60 over 1 crop 75

Ethanol productivity (l t-1) 48 over 1 crop 75

Ethanol productivity (t ha-1) 2880 over 1 crops 5600 crop-1

Reducing sugars Higher Comparatively lower

Grain yield (t ha-1) 2 to 6 --

Bagasse Higher biological value Comparatively lower

Fermentation efficiency 90 to 92 85 to 90

Ethanol cost per kilo liter (US$) 76.4 111.5

Ethanol production process Eco-friendly Comparatively not so

Ethanol burning quality Less sulphur More sulphur

In conclusion…

• Sweet sorghum can be cultivated over large areas in rainfed conditions

• Sweet sorghum is seed propagated and hybrid seed production system was worked out

• Since sorghum is an age-old crop, farmers have no difficulty in its cultivation and cultivation practices are simple and readily adoptable

Thank You

®

By-products from sweet sorghum

Stillage

Jaggery