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UNIVERSITY OF NAIROBI

Proceedings of the 8TH PHD Student-Led Seminar

on Communication of Research Findings at the

University of Nairobi, Faculty of Agriculture

Held on 22ND July, 2016

Venue: Room 205 Faculty of Agriculture Building

Proceedings prepared by Dr. Koech Oscar Post graduate Student Led- Seminar committee

Email: phdseminars@gmail.com

©July 2016

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1.1 Introduction

The 8th PhD seminar was held on 22nd July 2016 at the Faculty of agriculture, University of

Nairobi. The seminar kicked off at 9.00 AM and it brought together majority of postgraduate

students from various departments in the faculty. Prof. Kimenju, the Dean Faculty of Agriculture

chaired the meeting in conjunction with Prof Jasper Imungi. The chair welcomed the participants

and wished them success in their PhD research. The chair, Prof. Kimenju also welcomed the

participants and congratulated them for creating time to attend the important function of the

faculty..

1.2: Key note address

Prof John W. Kimenju

He began by noting that universities are known by the quality

of post graduate they produce. He applauded the attendees for

creating time to come to the seminar, which forms an

important part of quality assurance. He further noted that the

current world needs graduates with skills problem solving

skills, and this can only be achieved through experiential

learning. He emphasized the important role universities and

private partners have in creating an effective extension nsytem

of technologies. This requires applied research, which should

be a product of post graduate research. He also emphasized on

publishing research findings. On this regard, he stated that all

students should target publishing their work in high impact

journals, and this is now a university policy, which is also a requirement by CUE. To conclude

his speech, he affirmed to strengthen partnerships with industry and private partners in solving

problems facing production systems in Kenya.

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Prof Jesse T. Njoka

Prof. J.T Njoka gave a key note address and

emphasized on the need for research to solve real issue

affecting our communities. He recommended post

graduate research to also focus on innovation, and

produce products which can even be patented. He also

noted that student led initiatives is the way to go, if we

are going to change the thinking of the young

scientists.

Prof Jasper Imungi

Professor Imungi emphasized on graduates to focus on

agribusiness, and called for a paradigm shift of education

system, from the thought of white collar job to self

entrepreneurship. He emphasized on the need for development

of model farms to help in training our graduates, and linking

them to experiential learning. These can be attained easily with

the focus on quick income crops such as horticulture, which the

youth are easy to embrace. He further noted the need for

innovative and business incubation centre’s to help orient students to be innovators. This is one

way to increase job creation and employment.

Prof Robinson Kinuthia Ngugi

Professor Kinuthia emphasized on the need to mainstream

experiential learning. This should be started early in the career

development of our young student, probably, the students

should get introduced to field internship starting from 2nd year.

The need to increase collaboration with industry and other

private partners to actualize this is the way to go. He further

emphasized on the important need to inculcate soft life skills to our young graduates. He gave a

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good example of how the university has worked with Equity foundation, through partnership he

fast tracked to help students get experiential learning, through internship. The students working

with selected farmers have shown positive response in terms of learning simple basic things they

missed in class as agricultural scientist.

Key Note Speech - Mr. Zoravar Singh

Mr. Zoravar Singh, who is the general manager, Equity

Foundation, heading agricultural pillar was the chief guest

to give a key note speech on how university can partner

with private sector in steering development. He noted that

Equity Foundation has gone into partnership with UoN, as

the fast growing bank in Kenya and as the best University in

Kenya. He noted that the need for action research to

increase productivity, and create wealth for communities is

something that university should focus on. Equity

foundation has also provided platform for experiential

learning through internship opportunities. So far, the

foundation had worked with UoN, FoA in attaching 3rd years who gave positive feedback on the

gains and skills acquired. He reported on the existing future opportunities to work with post

graduate student. Already, the foundation is working with 3 MSc and 2 PhD students from the

UoN in areas of conservation agriculture, irrigation and mobile application in agriculture. He

further noted that we need to push the thinking in solving problems, where field application

research, is important, and this needs the inputs of professors. Mr. Zoravar assured to sternghten

future collaborations, and already they are considering setting centre for innovation, incubation

and entrepreneurial with UoN.

1.3: Presentation

After the keynote address, Prof. Kimenju and Prof. Imungi jointly chaired the three presentations

of the day. Each presenter took about 25 minutes. The following students presented their PhD

research findings.

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PRESENTER TITLE

[1] Luiza Munyua Abundance and diversity of nematode communities associated with bean (Phaseolus vulgaris L.) production in different agro-ecological zones of Western Kenya

[2] Julius Pyton Sserumaga

Genetics and Molecular analysis of Aspergillus flavus resistance in tropical Maize germplasm

[3] Awuor Elizabeth Ouna

Effect of Biochar generated from different technologies on soil productivity and yield of forage legumes grown in Mwea and Bura soils, Kenya

ABSTRACTS OF THE PRESENTATIONS

Resistance Mechanism and response to Aspergillus flavus Kernel infection in maize

Julius P. Sserumaga1,2, Dan Makumbi3, Godfrey Asea2 , Lee Simyung4, Kiarie Njoroge1, James W. Muthomi1, George N. Chemining’wa1, Moses Waswa2, Stephen Ochen2, Fred Ssemazzi 2 and

Gyoung-rae Cho5

1Department of Plant Science and Crop Protection, Faculty of Agriculture, College of Agriculture and Veterinary ,

University of Nairobi, P.O. 30197-00100, Nairobi, Kenya

2Cereals Program, National Agricultural Research Organization; National Crops Resources Research Institute, Namulonge, P. O. Box 7084 Kampala, Uganda

3International Maize and Wheat Improvement Center (CIMMYT), ICRAF House, UN Avenue, Gigiri, P.O Box

1041-00621, Nairobi, Kenya

4Biosafety Division, Department of Crop Life Safety, National Academy of Agricultural Science (NAAS) Rural Development Administration (RDA), 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju-si, Jeollabuk-do 54874,

Republic of Korea

5International Technology Cooperation Center, RDA, 370 Nongsaengmyeong-ro, Wansan-gu, Jeonju-si, Jeollabuk-

do 54874, Republic of Korea

Correspondence: Julius Pyton Sserumaga, Research Officer-Cereals Program, National Crops

Resources Research Institute (NaCRRI), National Agricultural Research Organization (NARO),

P.O Box 7084 Kampala, Uganda. Tel: 256-414-370-907. E-mail: j.serumaga@gmail.com

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Abstract

Kernel infection by Aspergillus flavus and sub-sequent pre-harvest

aflatoxin contamination of maize grain are a major production

problem in the East African Region and else in the world. Although

tremendous progress has been made elsewhere little efforts/success

has been achieved in East African region in developing and

identifying sources for resistance. This is attributed to luck of

understanding of the genetics of kernel infection by A. flavus.

Between 2014 and 2015 Nineteen inbred lines were crossed in a NC

Design II mating scheme to produce 90 hybrids to study genetic

nature of percentage kernel infection (PKI) by A. flavus and also to

estimate additive and dominance genetic variances. Across two years of study, combined

analysis of variance across years revealed that PKI1 was moderately significant (P < 0.01), PKI3

and KT were highly significant (P < 0.001) (Table 5). Environment was highly significant (P <

0.001) for all the traits; PKI1, PKI2, PKI3, PKI and KT (Table 5). Genotype was highly

significant (P < 0.001) for PKI3 and Tex, moderate significant (P < 0.01) for PKI, significant (P

< 0.05) for AUDPC, though not significant for PKI1and PKI2 (Table 5). Year x Env interaction

was highly significant (P < 0.001) for all the traits; PKI1, PKI2, PKI3, PKI, AUDPC and KT.

The GCA and SCA effects varied across years, which implied that percentage kernel infection

was greatly influenced by environments. GCA effects for different Percentage Kernel infection

intervals (PKI1, PKI2, and PKI3), Average percentage Kernel Infection (PKI), Area Under

Disease Progress Curve (AUDPC) and Kernel Texture (KT) are presented in table 13. Seven

inbred lines parents i.e. four male (parents 1, 3, 4 and 5) and three female (parents 1, 2, and 5)

had negative GCA values for PKI1, PKI2, PKI3, PKI and AUDPC while seven inbred lines

parents i.e. four male (parents 7, 8, 9, and 10) and three female (parents 3, 6, and 7) had positive

GCA values for PKI1, PKI2, PKI3, PKI and AUDPC. Narrow-sense heritability for PKI, PKI1,

PKI2, PKI3 and Tex was 53.2%, 46.4%, 454%, 50.7% and 72% respectively. Broad-sense

heritability for PKI, PKI1, PKI2, PKI3 and Tex 70.4%, 46.4%, 62.1%, 56.8% and 93.3%

respectively. Breeding procedures to handle both additive and dominance variances would need

to be used to improve resistance to PKI.

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Key words: Aspergillus flavus, Zea mays, breeding, inheritance, general combining ability,

genetics, percentage kernel infection, resistance, specific combining ability

Title: ABUNDANCE AND DIVERSITY OF NEMATODE COMMUNITIES ASSOCIATED WITH COMMON BEAN IN DIFFERENT AGRO- ECOLOGICAL ZONES OF WESTERN KENYA

Luiza Munyua1, R. D. Narla1, J. W. Kimenju1, J. E. Thies2 (1) Plant Science and Crop Protection, University of Nairobi, P. O. Box 29053 NAIROBI, KENYA

(2)Soil and Crop Science, Cornell University, 722 Bradfield Hall, Ithaca, NY, USA

Plant parasitic nematodes are a major threat to common bean production in Western Kenya, causing up to 60% yield losses, with root-knot nematodes (Meloidogyne spp.) being the most devastating. While bean is the most widely cultivated food legume in the tropics and subtropics and is the main source of protein in the diet, it is highly susceptible to root-knot nematodes and other plant parasitic nematodes with minimal chances of resistance. The interaction of nematodes with other soil borne pathogens results in disease complexes that are a major constraint in bean production due to the associated losses and increased costs of their management. A baseline survey and soil sampling was conducted in 60 smallholder farms in 2013 to establish the presence, abundance and diversity of plant parasitic and non-plant parasitic nematodes on small-holder farms in Western Kenya. Farms were located in three regions of western Kenya, representing four agro-ecological zones (AEZs). The resulting data informed the use of organic matter amendments (biochar and vermicompost) as viable options in subsequent field trials in suppressing the severity of plant parasitic nematodes and enhancing the beneficial, non-parasitic nematodes. Sixteen genera of plant parasitic nematodes and 14 genera of free-living, non-parasitic nematodes were enumerated. Meloidogyne spp., Tylenchus spp., Pratylenchus spp. and Scutellonema spp. were the most abundant of the plant parasitic nematodes enumerated in the four AEZs. Tylenchus spp. was most abundant in the lower midland humid (LM1), upper midland humid (UM1) and upper midland semi-humid (UM3) AEZs while Meloidogyne spp. was must abundant in the lower midland sub-humid (LM2) AEZ.

Effect of Biochar on some physical and chemical properties of soils from Mwea and Bura

ASAL regions in Kenya

1Ouna, E. A., Keya, S. O., 2Wanjogu R. K,1 Njoka T. J. 1Department of Land Resource Management and Agricultural Technology, University of

Nairobi. P. O. Box 29053-00625, Kangemi, Nairobi, Kenya.

2Mwea Irrigation and Agricultiral Development, National Irrigation Board of Kenya, P. O. Box 21, Wang’uru, Kenya

Corresponding author: Shellemiahkeya@yahoo.com

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Abstract Soil quality decline due to intensive cultivation and degradation

in Arid and semi-arid regions remain a challenge to food

security in sub-Sahara Africa amidst population increase.

Biochar offers potential to improve soil fertility in highly

degraded soils with low organic matter. However, the quality of

biochar used for soil amendment is influenced by production

temperatures and soil type and quantitative literature on its use

for soil amendment to improve soil physical and chemical

properties is still limited. The present study was undertaken to determine the effect of biochar

production technology on quality of the products for soil amendment. The effect of rice husk

biochar on soil amendment was conducted in Mwea and Bura agro-ecosystem under cereal-

legume production. The effect of pyrolysis temperature, thermal conversion rate of biochar

produced from traditional kiln and a modified carbonizer were examined. The physico-chemical

quality of biochar was determined by measuring product biomass, thermo-chemical rate of

conversion, percentage organic carbon and nitrogen, phosphors, pH, percentage fixed carbon-,

ash, and volatile matter. In order to determine effect of biochar produced from the two

technologies on soil, soil texture of Mwea and Bura soils was characterized before amendment.

Initial amendment was carried out by direct application of 150 g of biochar in the rhizosphere

and later at a rate of 3, 10, 30 ton ha-1 at a depth of 0-30 cm and incubated in open plots grown

with Stylosanthes or Dolichos. The soil chemical quality was analyzed for organic carbon,

nitrogen, changes in pH, Ec, bioavailable P and mineral nutrients at the rhizosphere. Effect of

biochar on soil moisture release characteristics between field capacity and crop lower limit of

15kPa was used to calculate plant available water before subjecting the data for analysis. Soil

bulk density or moisture content by oven dry weight method at 105 C̊ and results used to

calculate and analyze porosity. Hydraulic head conductivity according to Darcy’s law.

Percentage organic carbon was determined by back titration after oxidation of 0.2 g of soil

samples with dichromate and concentrated sulphuric acid followed by titration against ferrous

sulphate solution. Percentage N content was determined using Kjedhlah’s nitrogen digestion

method, and phosphorus by Mehlich’s double sandwich method for acidic and alkaline soils.

Electrical conductivity and pH was measured at a ratio of 1:20 (w/v) of biochar: distilled water

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or 1:2.5 of soil: distilled water. Results showed highest carbonization temperatures 736 ͦC in

modified carbonizer and 349 ͦC traditional kiln. Phosphorus concentration and pH was

significantly higher in biochar produced from modified carbonizer than biochar from traditional

kiln and were at 147 and 214 ppm; and 8.1 and 7.2 respectively. Percent organic carbon was

significantly lower in biochar from modified carbonizer than biochar from traditional kiln and

was at 0.45% compared and 1.38% respectively. Percentage fixed carbon in biochar generated

from modified carbonizer was significantly higher than in biochar generated from traditional

kiln, and was at 26.45% and 16.45% respectively. Percentage volatile matter from biochar

generated from modified carbonizer was significantly higher compared to biochar that from

traditional kiln and was at 63.44% and 48.63%. Soil texture results exhibited Mwea soils to

contain 57.4% clay, 42.4/% sand and 0.2% silt while Bura soils contained 37.6% clay, 60.4 %

sand and 2% silt. Mwea soils amended with biochar showed significantly higher concentration

of phosphorous, pH and N in soils treated with biochar from modified carbonizer than soil

treated with traditional kiln and were at 120 and 75 ppm and control of 40 ppm; and a pH of

7.2 and 8.1.Total nitrogen levels increased from 0.12 to 0.16 in modified carbonizer. Significant

increase of available phosphorous in Bura in soil from both treatments (21.6 and 21 ppm) than

control (12.4ppm) soils but not between treatments. Significant increase in % organic C was 0.77

after one and half years in soils treated with biochar from traditional kiln compared to control at

0.47 in Bura soils. Under laboratory based studies, plant available water capacity was

significantly higher in soils amended biochar with than control. Compared to controls, soils that

were amended with biochar increased hydraulic conductivity from 0.944 in control to 1.84, 3.14

and 12.4 cm3 min-1 for Bura soils amended at 3, 10 and 30 t ha-1 respectively. In Mwea soils

conductivity increased from 0.36 in control to 1.08 cm3 min-1 for 3 tons ha-1. In all cases water

retention in treated soils at field capacity increased but reduced residual water at 15 bar. This

resulted to increased plant available water from 16 in control to 24.9, 26 and 30.8 cm3 cm-3 in

Bura soils; and from 12.8 in control soils of Mwea to 15.7, 20.9 and 18 cm3 cm-3 in sols amended

at 3, 10 and 30 t ha-1 respectively. In conclusion biochar produced from modified carbonizer is

superior for soil amendment compared to similar material from traditional kiln, particularly the

areas of Mwea here soil are acid and of low N and similar soil types within East Africa. Biochar

improved soil physical and chemical properties; nitrogen, phosphorous, pH, density, improved

porosity and water improved water retention volume, rate of water movement and plant available

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water but more research would be required for Bura. These factors have a resultant enhancement

on crop water use efficiency, reduction of soil compaction and improvement of heat exchange

transfer. Estimating the value of biochar as a carbon stock on agriculture requires all inclusive

measurements of sub-soil, plant biomass, and biological functions in order to develop carbon

management index as a component of soil fertility. Possibility of formation of toxic poly

aromatic hydrocarbons compounds like polychlorinated dioxins and furan due volatilization of

chlorine during pyrolysis and incomplete combustion could result in contamination of biochar.

Evaluation of PAH is important for purposes of setting their maximum limits of PAH in soil.

Key words: degraded soils, soil fertility; biochar; water use efficiency

1.5: Closing remarks

Prof. Kimenju gave closing remarks by stressing on the need for all PhD students to attend

research, which is a way of value addition and quality assurance. He also re-emphasized on the

regulation by FoA that each and every student must give at least 2 seminar presentations before

being allowed to submit thesis for examination. He also stressed on the need to have at least two

journal publications in a good peer review journal, impact factor more than 2.5, before degree

award after defense. This is only possible if the students start early to prepare manuscripts and

use the seminar series for value addition, before submission to journals.

1.6: Next Seminar

The next seminar shall be in September, a date to be communicated by the PhD seminar

secretariat.

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List of Participants

Present

1. Prof. J.W. Kimenju

2. Prof. J.T Njoka

3. Prof. R.K Ngugi

4. Prof. J. Imungi

5. Dr. Koech Oscar

6. Dr. R. D. Narla

7. Dr. D. W. Miano

8. Dr. Fredrick Ayuke

9. Elizabeth A. Ouna

10. Luiza Munyua

11. Philista Malaki

12. Joseph H. Nguetti

13. Julius Sserumanga

14. Joseph K. Njuguna

15. Charles Nkonge

16. Samuel Were

17. Gitaru Harun

18. Sani A. Kende

19. Suleiman M. sabiu

20. Yuga Mario Enock

21. Stety Authur

22. Castro Kipkorir

23. Dasel Kaindi

24. Tadesse Yohannes

25. Wabwire Moses

26. Ruth akinyi

27. Karen Wanbui Gitau

28. James Barasa

29. Paul Wesonga

30. Angwaria Paul

Apologies

1. Dr. Judy Symbua

2. Prof. Moses Nyangito

3. Dr. Oliver Wasonga

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PROGRAMME OF THE PRESENTATIONS

POST GRADUATE STUDENT-LED SEMINAR PROGRAMME

22nd July, 2016

8TH PhD Communication of research findings by PhD students in the Faculty of agriculture

Venue: Room 205 Faculty of Agriculture Building

PHOTO OF THE 6TH SEMINAR ON 11/03/2016 PHOTO OF PRO. NANCY KARANJA

GIVING KEY NOTE ADDRESS DURING THE 7TH PHD SEMINAR

ON 11TH March 2016

QUESTION AND ANSWER SESSION DURING THE 7TH PHD SEMINAR ON

11TH March 2016

DAY : 22nd July, 2016 Time Activity/Title Moderator/Speaker/presenter

8.00 -

8:30am

Arrival and Registration Postgraduate seminar committee

SESSION 1: OPENING SESSION

Session Chair: Prof. John W. Kimenju/ Prof. Michael Okoth

Opening Prayer Luiza Munyua

9.15 am Introductions and

Theme

The Dean, Prof. John W. Kimenju

Welcome Remarks Prof. Prof Nancy Karanja

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Key Note address Mr Zoravar Singh - Key note speech on the partnership

between Equity Foundation and UoN

Key Note address Prof. Ratemo Michieka

9:15 am

- 1:00

pm

PRESENTATIONS

Rapporteur: Mr. Dennis Olila and Josphat Njenga

PRESENTER TITLE

09:55 –

10:35

[1] Luiza Munyua

Abundance and diversity of nematode communities associated with bean (Phaseolus vulgaris L.) production in different agro-ecological zones of Western Kenya

10:35 –

11:15

[2] Julius Pyton Sserumaga

Genetics and Molecular analysis of Aspergillus flavus resistance in tropical Maize germplasm

11:15 –

11:55

[3] Awuor Elizabeth Ouna

Effect of Biochar generated from different technologies on soil productivity and yield of forage legumes grown in Mwea and Bura soils, Kenya'

12:00-

12:30

Wrap up: Prof. Prof. Robinson Kinuthia Official Closing: The Dean, Prof. John W. Kimenju

Closing Prayer- Awuor Elizabeth Ouna

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Photos during seminar

Compiled by: PhD Seminar Committee,

Dr. Oscar Koech

Contact: phdseminarscavs@gmail.com