Faculty of Agriculture

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    The influence of soil water content and nitrogen supply on growth, yield and polyphenol content of selected tea [Camellia sinensis (l.) O. Kuntze] clones in Kenya
    (Egerton University, 2008-04) Cheruiyot, Erick Kimutai
    Tea is a major foreign exchange earner in Kenya and it accounts for about 24% of the total value of the domestic exports for the last 10 years. The sector employs 10% of Kenya’s population directly and indirectly, and contributes to infrastructural development which includes construction of schools and health facilities, rural access roads and rural industries. However, tea suffers frequent droughts with significant yield decline, often accompanied by plant deaths, a condition which seems to be worsened by fertilizer input. The objectives of this work were to determine: i) the critical minimum soil water requirements in selected tea clones and show how it varies with nitrogen (N) supply ii) the effect of N supply and progressive decline of soil water content on tea shoot growth, leaf yield and black tea quality iii) the levels of tea polyphenols and define their association with water stress in tea and their suitability as indicators for drought tolerance. Two experiments were set up in a rain-out shelter at Tea Research Foundation of Kenya (TRFK) and a field experiment conducted at three different field sites in tea growing areas. The first experiment consisted of six different tea clones which were subjected to 4 levels of soil water content (SWC) (38, 30, 22 and 14% v/v) for 12 weeks. The second experiment consisted of clone BBK 35 treated with 5 different rates of N (0, 75, 150, 225 and 300 kg/ha) using NPKS (25-5-5-5) fertilizer material, and 5 levels of SWC (38, 34, 30, 26, 22, 18% v/v). Shoot and leaf growth, dry matter partitioning, photosynthesis, stomatal conductance, transpiration, leaf anatomy and shoot polyphenol content were determined. The field experiment consisted of clone BBK 35 with five rates of N, similar to the rain-out shelter and where shoot population density and yield were determined during dry months. SWC limit for tea was shown to be about 20% v/v and that fertilizer supply increased the susceptibility of tea to drought. Contrary to earlier speculations that fertilizer raises the optimal SWC for tea, it emerged that fertilizer rates above 200 kg N ha-1 influenced assimilate partitioning to shoot and foliage, making tea more vulnerable to drought effect. Clones with high total polyphenol content and whose levels varied less with changes in SWC were more tolerant to drought. Two catechin variants, epicatechin and epigallocatechin correlated with SWC, water stress index and shoot growth in tea, which suggests they are potential indicators for drought stress in tea.
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    Factors influencing the application of information and communication technology in the management of agricutural informtation in Nakuru District, Kenya
    (Egerton University, 2009) Ombati, Justus Moturi
    Agriculture is an important sector in the Kenyan economy. It contributes 26.6% to the GDP, creates employment to about 80% of the rural population, supplies raw materials to industries and earns the country the much-needed foreign exchange. There is need, therefore, to develop this sector. Agricultural infonnation is one critical resource in agricultural development. It is the basis of a modern and progressive agricultural sector. This, therefore. demands that agricultural infomiation be generated, tested, packaged and readily made available to the users. Effective use of infonnation and communication technology (ICT) would greatly improve agricultural information management for overall development of the sector. Studies, however, indicate the use of ICT-based systems for the management of agricultural infonnation within and between me various subsystems of the agricultural sector is limited. The overall purpose of the study was to establish the actual status of ICT usage in management of agricultural information and determine conditions inhibiting the implementation of the ICT usage. It investigated the current state of agricultural information management and determined the factors that influence the effective application of ICT-based systems in this Work. It further determined and documented the requirements for implementing an ICT-based system that would interface the management of agricultural information within and between the agricultural research, extension service, training institutions and farmers in Nakuru District Kenya. A modified Delphi technique was used to obtain both qualitative and quantitative data. Respondents in the study Were drawn using proportionate random sampling from research scientists, the technical extension staff, teaching staff of agricultural training institutions, and farmers in the district. Questionnaires were used to collect data. The statistical package for social sciences (SPSS) was used for data analysis. T-test at on 5 0.05 was used to test hypotheses, accordingly. The study established that there were low levels of infonnation processing using ICT within and between the major subsystems of the agricultural sector in the district. Lack of resources, computer illiteracy, poor infrastructure and insufficient govemrnent initiative has been found to be major impediments on the utilization of this technology. lnvestrnent in science and technology, infrastructure development, and promotion of education are some of the measures that would enhance adoption of ICT in the management agricultural information for agricultural development.
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    Diversity of banana streak virus in Kenya
    (Egerton University, 2009-04) Karanja, Laura Shali
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    Diversity of banana streak virus in Kenya
    (Egerton University, 2009-04) Laura, Shali Karanja
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    A comparative analysis of the structure and performance of Agricultural science and Technology policy system in Kenya and Uganda
    (Egerton University, 2009-09) Godiah, Lawrence Mugunieri
    Despite the acknowledged importance of agricultural science and technology (AS&T), little is known about the structure and performance of AS&T policy system in developing countries. The structure and performance of this policy system in Kenya and Uganda was analysed using a preliminary ‘system components-shift effects’ framework. The system components comprised of agricultural research, extension, education and transboundary technology transfer. The impact of these components was modified by three-levels of shifteffects: policy environment, institutional arrangements and micro-conditions to give a 3x4 matrix of potential determinants of system structure. The structure was hypothesised to exist in three different generations: first, second and third. Uganda was presumed a first generation system and Kenya second. The potential system structure was separately related to three performance indicators, namely; technical efficiency, technical change and efficiency change using different econometric techniques in order to delineate important determinants of structure. The results indicated that the preliminary three-level framework can be used as an effective tool for delineating the structure of AS&T policy system in developing countries. Furthermore, the structure of the policy system differed between the first and second generation systems. At policy level, transboundary technology transfer was significant and positive only in second generation systems whereas agricultural education and research expenditures were important in both. At institutional level, intellectual property rights regulatory system had impact only in second generation systems, agricultural extension decentralisation had negative effect in first generation systems, whereas agricultural research coordination had no impact in both systems. At micro-level, literacy within the agricultural labour force was significant in second generation but not in first. However, domestic research outputs had significant impact in first generation systems but not second. The same applied to policies geared towards reducing transaction costs in accessing technologies. These results imply that generation specific AS&T policies should be encouraged instead of collective generic policies for all developing countries. Although lack of data precluded effective application of the three-level framework, this study offers opportunities for further research in this area, which has previously been driven by data and not ideas.
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    Factors influencing adoption of drought tolerant wheat varieties in the arid and semi-arid lands of Narok and Kajiado Districts-Rift valley Province of Kenya
    (Egerton University, 2010-04) Ndiema, Alice Chesambu
    Adoption of agricultural technologies by farmers is influenced by a number of factors, which include the farmer and farm attributes, technology characteristics and institutional factors. It is on this premise that drought tolerant varieties (DTV) of wheat were developed for production in Arid and Semi Arid Lands (ASAL). This study was designed to assess low adoption by describing and comparing factors that have influenced adoption of DTV in the (ASALs) of Narok and Kajiado districts of Rift Valley Province-Kenya. A sample size of one hundred and eight (108) wheat farmers with seventy two (72) from Ololung‟a division of Narok district and thirty six (36) from Isinya division of Kajiado district were randomly selected by use of random numbers sampling technique. Farmers‟ perceptions of DTV of wheat, adoption levels and the influence of personal, socio-economics and institutional factors on adoption were investigated. The data was collected using a validated questionnaire and analyzed using SPSS for windows. Generally, the adoption levels were very low. Farmer perception on (DTV) was very low (0.9%) with majority of the farmers (77.8%) being uncertain of the objective of the technology and its benefits Eighty seven point nine percent (87.9%) of the farmers identified input cost as a major constraint and 85.1% lacked the relevant information. Opportunities for adoption cited by 91.6% of the respondents included the availability of the required seed. There was no statistical significant difference in perception between the farmers of Narok and Kajiado districts. However, there were significant differences in adoption levels with the average percentage for Narok mean of 1.58 being higher than Kajiado mean of 1.33 with a t-test value of -2.497; (P<0.014; α=0.05. Age, gender, and education did not have any statistical significance relationship in the adoption of DTV but farm size, land tenure system and extension services were statistically significant.
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    Genetic parameters and quantitative trait loci mapping in tea, Camellia sinensis (l.) O. Kuntze
    (Egerton University, 2010-06) Kamunya., Samson Machohi
    Efficient breeding and selection of elite tea (Camellia sinensis (L.) O. Kuntze) clones require sound knowledge and understanding of genetics associated with yield, quality and tolerance to biotic and abiotic stresses. A series of experiments were carried out to elucidate the genetic parameters and map quantitative trait loci (QTL) for agronomic and quality attributes in tea. The combining abilities and heterosis for yield, drought tolerance (DT), and quality traits (percent total polyphenols (%TP), fermentability (FERM), theaflavins (TF), thearubigins (TR) and pubescence (PUB)) in tea were estimated in a 4 x 4 full diallel analysis. Generally, parents with good combining ability produced progeny with above average performance for all the evaluated traits. The general combining ability (GCA) effects were significant for yield, %TP, FERM, DT, TF, TR, PUB and bud weight, while specific combining ability (SCA) effects were significant for %TP, FERM, PUB and bud weight. Strong maternal effect for all traits was evident except for thearubigins and bud weight signifying the importance of female parents in breeding for yield, DT, and diversified tea products such as silvery tips. The heterosis analysis revealed that the mid-parent heterosis (MPH) and the betterparent heterosis (BPH) averaged across the families, were high for fermentability (MPH: 108.5%; BPH: -12.82) and DT (MPH: 16.44 %; BPH: 2.30%) but not so for yield (MPH: 2.17%; BPH: -5.09%) and total polyphenols (MPH: -2.81%; BPH: -5.71%). The heritability estimates for yield (h2 = 0. 44 ± 0.16; H2 = 0.56 ± 0.15), DT (h2 = 0.61 ± 0.06; H2 = 0.96 ± 0.01) and fermentability (h2 = 0.45 ± 0.04; H2 = 0.98 ± 0.01) were high indicating that the three traits are highly heritable and could be improved through hybridization and judicious clonal selection. Estimates of genetic gains indicated that moderate gains are achievable on clonal selection for characters such as yield and fermentability at 14.1% and 8.9%, respectively, while DT and PUB registered higher gains at 20.6% and 30%, respectively, based on h2. Mapping of QTL linked to yield, %TP, DT and shoot traits was assessed on a pseudotest cross comprising 42 clonal progeny between clones TRFCA SFS150 and AHP S15/10. QTL associated with root knot nematode resistance were investigated on a different cross consisting of 41 clonal progeny arising from TRFCA SFS150 and TRFK 303/577. Bulk segregant analysis was performed followed by complete genotyping. Out of 260 informative markers, 100 markers that showed 1:1 segregation were used to construct a linkage map. The map contained 30 (19 maternal and 11 paternal) linkage groups that spanned 1411.5 cM with mean interval of 14.7 cM between loci. A total of 64 QTLs controlling various traits across the two sites were detected. Of these, QTLs linked to YLD-T, YLD-K, DT-K and PUB were localised at 2 cM, 2.7 cM, 3 cM and 1.4 cM from markers OPG-07-2800, E-AGC/M-CAG- 725, OPT-18-2500 and OPO-02-650, respectively. No QTL was detected at both sites, which showed strong genotype x site interaction (G x E). Marker OPF-09-600 that co-segregated (P < 0.0000) with susceptibility to the root knot nematode was mapped at 0 cM from locus OPF- 09-600 on linkage group 8. Considering the long time expended in developing improved tea varieties, the identification of putative QTLs tightly linked to agronomic traits augmented by known genetic parameters provide room for marker-assisted selection thereby hastening tea improvement efforts.
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    Determinants of adoption of shade coffee technology and the role of agroforestry in the productivity and profitability of coffee in Imenti South District, Kenya
    (Egerton University, 2011-03) Ithinji, Gicuru Kirimi
    Agro-forestry has continued to receive increasing attention from researchers and policy makers’ especially in coffee farming systems but there is lack of sufficient evidence on its role in productivity and profitability of coffee farming in Kenya. There is also lack of empirical evidence on whether factors that influence adoption of shade technology have the same effect on productivity and profitability of coffee. The general objective of the study was to examine the adoption of agroforestry-based coffee management systems and the role of these systems in increasing the productivity, and profitability of smallholder coffee enterprise in Imenti South District. The study also extends the application of the Tobit model in the realm of analysis of farm productivity and profitability. Specific objectives included categorization of smallholder farmers into adopters and non-adopters of shade technology, productive and non-productive farmers, profitable versus non-profitable coffee farms using the local means as cutoff points. A structured questionnaire was administered to a representative sample, chosen through multistage sampling, of 346 smallholder farmers in Imenti South District of Kenya. First, descriptive statistics, t-tests and chi-square analyses were used to explore socioeconomic characteristics of adopters and non-adopters of shade coffee technology, productive versus non-productive farmers, as well as profitable versus non-profitable coffee farms. Using the sample mean for binary categorization of coffee farming households, 40 percent of the sample farm households were effectively classified as adopter of shade coffee, 44 percent was classified as productive coffee farmers, while about 43 percent of the farm households were classified as profitable coffee farming households. Socioeconomic characteristics of the productive and non-productive farmers, as well as profitable versus non-profitable farming households, were different and hence requiring different sets of stimuli to increase productivity and profitability. Second, separate Tobit models were then used to examine factors that determine the rate and intensity of adoption of shade technology, as well as determinants of productivity and profitability of coffee/agroforestry system. The Tobit results show that different sets of socioeconomic factors determine the rate and intensity of adoption of coffee shade technology, productivity and profitability requiring proper understanding of the interplay of these factors in order to promote appropriate policy incentives. Policy implications are drawn.
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    The pathosystem of napier stunting disease in Western Kenya
    (Egerton University, 2012-11) Obura, Evans Odhiambo
    Napier stunting (Ns) disease, caused by Rice Yellow Dwarf (RYD) phytoplasma, is a big threat to Napier grass production and food security in Kenya. The disease destroys fodder completely, with a devastating impact on livestock farmers. To control the disease, this study described the four components of Ns-disease pathosystem; phytolasma itself as the causative pathogen, the host plant susceptible to phytoplasma, the insect as a competent vector, and the alternative sources of phytoplasma inoculum in western Kenya. The study also developed quicker, more economic and robust methods for diagnosis of Ns-disease. The vector was identified through laboratory transmission experiments with field collected insects, while the alternative host grasses were discovered by molecular detection and characterization of natural phytoplasmas in symptomatic grasses. The local Napier grass germplasm characteristics were studied for genetic diversity and Ns-disease response using Amplified Fragment Length Polymorphism (AFLP) technique and laboratory transmission experiments. Molecular diagnosis of Phytoplasma in test plants and insects was performed by nested polymerase chain reaction (PCR) and loop mediated isothermal amplification of DNA (LAMP), based on phytoplasma 16S and ITS gene sequences. The study discovered that Ns-disease is transmitted by insect vector Maiestas (=Recilia) banda (Homoptera: Cicadellidae). The vector showed feeding preference to closely related pennisetum species: Napier grass and Pearl Millet. The RYD phytoplasma was transmissible to Cereals under laboratory conditions. It was also discovered in wild Thatching grass Hyparrhenia rufa, where it is pathogenic. A closely related phytoplasm; Bermuda grass white leaf (BGWL), was also discovered in pasture grass Cynodon dactylon. The phytoplasma therefore circulates between Napier grass and other wild grasses corresponding to a polycyclic epidemic. AFLP analysis divided the local Napier grass germplsm into 4 genetically distinct groups; however, the quality of this germplasm as source of resistance to Ns-disease was poor, and none of the varieties showed resistance to phytoplasma infection, which explains the high prevalence of Ns disease in western Kenya. Based on Ns-disease pathosystem, this study recommends the following disease control strategies: elimination of infected plants (Napier grass, Bermuda grass and Thatching grass), certification of planting material and control of the insect vector M. banda. There is also need to extensify resistance screening to a much wider germplasm, both wild and improved varieties.
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    Characteristics, feeding and marketing practices of the emerging peri-urban Camel production system in Isiolo County, Kenya
    (Egerton University, 2013-05) Noor, Issack Mohamed
    Pastoral camel management strategies in northern Kenya, characterised by free herd mobility that enables efficient utilisation of rangeland resources, is slowly but progressively adopting restricted camel foraging within the vicinity of urban milk market outlets as seen in Isiolo town. The emerging peri-urban camel production system (PUCPS) has potential livelihood benefits to households but there are emerging pressures that can impede its sustained development and benefits. Key emerging pressures are on forage feed resources and market oriented milk production. This study explored options for improving feeding and marketing practices in PUCPS, guided by four research questions. The questions were: what are the key defining characteristics of PUCPS; what are its drivers for development; what are the challenges to its development; and what are the interventions to support its sustained development? Data were obtained from cross sectional surveys, focus group discussions, laboratory analyses of camel forages and supplementary feeding trials. Descriptive and inferential statistics comparing pastoral and peri-urban camel systems in Isiolo County indicated that camels remain the primary source of livelihoods even as pastoralists‟ transition to semi-sedentary urban lifestyle and milk is the key product. The drivers behind the emergence of PUCPS in Isiolo were: progressive sedentarization of pastoral communities with strong tradition for consumption of camel milk, a niche urban market for camel milk in Nairobi, and reliable (tarmac) road to urban markets. Compared to pastoral, peri-urban systems exhibited greater market orientation with large volumes of marketed milk, 2.4 times more sale of steer surplus stock (25.8 vs 62.8%) and purchase of 2.2 times more heifer breeding stock (12.3 vs 27.5%). The growth of Isiolo PUCPS has been rapid but is sensitive to disruption of peace and stability, market barriers due to poor milk hygiene practices and vulnerability to trypanosomosis and haemorrhagic septicaemia disease incidences that cause economic losses. Seasonal fluctuations in forage nutritive values were marked, being superior during wet season than in dry season (mean CP 15.70% vs 9.86%; mean CF 23.22% vs 32.57%; mean NDF 44.38% vs 53.15%). Consequently, wet season milk off-take declined by 33% during dry season and by 55% during severe drought which substantially reduced milk volume sold by 36% during dry season and by 60% during severe drought. Supplementary feeding with maize germ-based diet significantly (p<0.001) improved milk yield of lactating camels by 26% over acacia pods-based diet and by 50% over rangeland foraging and browsing. Major challenges to the continued development of Isiolo PUCPS are reported and the relevant interventions proposed. It is concluded that camel production in peri-urban areas near towns like Isiolo is gaining significance as an economic activity due to commercialization of camel milk
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    Biochemical and molecular identification of key pathogens causing mastitis in dairy goats on smallholder farms in Kenya
    (Egerton University, 2014-04) Shivairo, Robert Shavulimo
    Mastitis in dairy goats was investigated with the objective of establishing the effect of management and the identification of the key causative agents through common diagnostic procedures of somatic cell counts, bacteriological identification and, for the first time in goat mastitis, by use of Polymerase Chain Reaction. A cross-sectional survey, using a structured questionnaire was conducted in three agro-climatic regions of Coast, Nyanza and Rift Valley, with goat keeping clusters serving as sampling sub-units. The focus of the questions was on housing, feeding, labour, water sources, record keeping, socio-economic status of respondents and availability of extension service. California Mastitis Test (CMT) was done at the farm-level, Somatic Cell Counts (SCC) and bacterial isolation were done in the laboratory. Polymerase Chain Reaction (PCR) on the two key bacteria, Staphylococcus aureus and Escherichia coli were subsequently carried out on 16 randomly selected samples representative of the three dairy goat keeping agro-ecological zones. The management survey indicated that 56.9% of respondents were peasant farmers only 12% of respondents could afford hired labour. There was evidence of scarcity of quality water, with only 9% using water from rain catchment and the rest depending on wells, dams and rivers. There was no training package on dairy goats. The CMT scores for the two key organisms ranged between 2 and 3, making it a reliable test for udder infection. Somatic Cell Counts (SCC) was determined for 239 samples with scores ranging between 0.248 106 and 1.693 106 with a mean of 0.869 106. This study demonstrated significant SCC variations amongst the breeds, there was also significant variation in SCC scores for various locations. Other factors in the study were lactation length and parity all of which affected SCC scores. The bacterial isolation showed dominance of Staphylococcus aureus and Escherichia coli respectively. The two species of bacteria are significant indicators of the state of hygiene on the farms. The PCR identification of the two organisms showed that they were distributed in all three regions of study. There is a need for more intensive studies on the various diagnostic tools especially CMT, SCC, bacteriology and PCR to enable the development of quality standards in Kenya for goat milk which do not exist at the moment.
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