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A realist explanation of long run development interventions contexts, adaptations and outcomes of dairy improvement in Kenya.Miroro, Obadia Okinda. 04 September 2014 (has links)
Despite continued pursuit of development interventions to improve people’s livelihoods and reduce poverty, intended and actual outcomes of developments interventions may differ. Some scholars attribute this variation to flawed conceptualisation of development interventions while others view this divergence as evidence that implementation processes are complex and actual outcomes result from adaptations of the interventions by actors. To move beyond the discursive approaches to analysis of development interventions, this thesis addresses the question how do actors adapt them, why and with what outcomes in the long run? Empirically, it looks at how project officers and farmers adapted the National Dairy Development Project (NDDP), a dairy intervention implemented in Kenya between 1980 and 1995, and its long run outcomes. The intervention promoted zero grazing, intensive management of dairy cattle whose implementation by farmers was expected to increase land productivity as a means to address land scarcity, increase milk production and reduce poverty through generation of incomes from milk sales.
The methodology of this thesis links mechanisms, contexts, and outcomes, three elements of realist explanation, to understand adaptations and outcomes of development interventions. Through thematic synthesis of in-depth interviews and analysis of project documents, this thesis explains adaptations and long run outcomes of the NDDP. Findings reveal that developers and farmers adapted several components of the intervention. With close reference to context, incentives and continuity pressures, this thesis utilises intervention effectiveness and matching mechanisms to explain how project officers adapted the NDDP. Further, through fit and resistance mechanisms, this thesis explains how farmers adapted zero grazing in the context of inadequate fodder, labour shortage and lack of resources to invest in dairy. In the long run, findings show that the intervention diminished as evident in coexistence of indigenous and modern dairy technologies and non-implementation of any dairy technologies by farmers. Despite adaptations of zero grazing by project officers and farmers, intensification of dairy cattle management has diminished in the context of resource constraints, neoliberal policies and labour shortage. Consequently, the objective to increase land productivity through intensive dairy cattle management, the rationale for initiation of the intervention, remains unresolved. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2014.
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Variety for security : a case study of agricultural, nutritional and dietary diversity among smallholder farmers in western KenyaNg'endo, Mary January 2015 (has links)
Agricultural biodiversity, commonly referred to as agrobiodiversity, is that part of biodiversity that is geared towards agriculture and food production. Agrobiodiversity is said to contribute much to food and nutrition, but there is lack of data confirming this, particularly from Eastern Africa. To assess the extent of agrobiodiversity on smallholder farms and in local markets and to connect these to food intake and perceptions of food security among smallholder farmers in Western Kenya, the thesis asks four main research questions: (i) What is the extent of food plant diversity in smallholder farms, the bio-physical and socio-economic factors influencing it and the contribution of this diversity to the household's food needs? (ii) What is the relationship between agricultural and dietary diversity? (iii) What linkages are there between agricultural and nutritional diversity? (iv) How does access to agrobiodiversity in local markets contribute to meeting household food needs and what is the extent of smallholder farmers' integration into these markets? Through a combination of focus group discussions, farm and market surveys conducted across three time points, results indicate that: (i) higher food plant species richness is found on farms managed by wealthier and older households. However, these households are not more food secure than the rest, (ii) while there is a lack of a strong relationship between agricultural and dietary diversity, dietary diversity is instead significantly influenced by socio-economic factors including a household's wealth status, ethnicity and education level, (iii) despite a diversity of locally available on-farm and market food species meeting existing macro-and micro-nutrient needs, there is a general lack of understanding of this diversity as food shortage months coincide with a lack of maize despite high availability of a diversity of other foods not only to replace the maize but also to contribute to a diverse diet, (iv) smallholder farmers rely on multiple food sources, with markets mainly for sourcing cereals, fruits and animal source foods. There is also low integration of smallholder farmers as sellers in local markets. Together, the four case studies show interlinkages across food availability, accessibility and utilisation, which when addressed with equal weight, could unlock local agrobiodiversity's potential as a path to food and nutrition security of smallholder farming households.
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Can livelihood approaches adequately evaluate the determinants of food insecurity to inform interventions in Kenya?Mutunga, Nancy Muthoni. January 2012 (has links)
Food insecurity has remained pervasive for most Kenyan livelihoods despite the implementation
of substantive interventions by the government and its development partners, since it gained
independence in 1963. The inability to isolate distinct determinants of food insecurity for each
livelihood group has led to interventions and solutions that have entrenched food insecurity
rather than mitigate it. The key impediment to a livelihood-level analysis of food insecurity is
the use of data and information collected at district-level administrative units, coupled with the
absence of a robust analytical methodology.
This study set out to identify determinants of food insecurity for three distinct livelihood groups
in Kenya, namely the pastoral, agro-pastoral and marginal agricultural groups. The study also
sought to empirically evaluate incremental impacts of identified determinants of food insecurity
for each group. The outcomes were intended to inform the selection of particular indicators in
order to target, monitor and identify important inter-relationships between variables for each
livelihood group.
Few studies have applied heterogeneous ordered logit regressions to livelihood-level data to
evaluate food security determinants among livelihood groups and a comprehensive livelihood
analysis of the determinants of food insecurity has not yet been undertaken in Kenya. Yet,
Kenyan livelihoods are highly diverse, and livelihood characteristics transcend administrative
boundaries.
This study used a heterogeneous ordered logit to model determinants of food security in Kenya.
The variables were: conflict, HIV/AIDS, rainfall, flooding, proximity to markets, migration
patterns, food consumption sources, income contribution sources and own farm production.
Results of significance tests and residual variability from the ordered logistic regression led to
the identification of important determinants of food insecurity in each of the three livelihoods.
The degree to which each of the variables was influential in accentuating food insecurity in each
livelihood, was also evaluated. Determinants of food insecurity and their inter-relationships
informed the selection of indicators for monitoring.
Proximity to markets seemed to have a marked impact on food security in the pastoral, agropastoral
and marginal agricultural livelihood groups. Conflict was influential in determining
food insecurity, particularly for the pastoral and agro-pastoral livelihood groups. HIV/AIDS
prevalence in the community was critical in determining food security status for the marginal
agricultural and agro-pastoral livelihood groups. Rainfall was an important determinant of food
insecurity in all the groups. Flooding had no significant impact on food insecurity. The results
showed that an increase in the number of food sources improved food security in the pastoral,
agro-pastoral and marginal agricultural livelihood groups. A diversity of income sources
improved food security in the pastoral and agro-pastoral livelihood groups. The pastoral
migration pattern seemed to have a substantial impact on food security especially in the pastoral
and agro-pastoral livelihood groups. Own farm production was also influential in determining
food security in both groups.
The study outcome provides a basis for identification of important monitoring indicators
including agro-climatic, trade and market processes, migration dynamics, income and food
sources and the stability, settlement patterns, key livelihood and coping strategies in the three
livelihood groups. The strong inter-relationships between variables suggest that multiple
variables need to be monitored concurrently to address livelihood food insecurity in Kenya. The
findings suggest that livelihood approaches are central to identifying determinants of food
insecurity in Kenya. The outcomes of the study provide a basis for informing interventions
intended to reverse food insecurity in Kenya for each distinct livelihood group. Further research
could include an analysis of the impacts of seasonality, an in-depth analysis of the markets and
their marked influence in affecting food security, and applications of similar methodologies to
evaluate of the food insecurity of livelihood groups that were not covered in this study.
Outcomes of this work are expected to provide a basis for formulating livelihood-specific
interventions in Kenya. The results will provide a platform for further interrogation of important
determinants of livelihood food insecurity by governments, researchers, and development
partners. Aspects of the methodologies applied in this study can be replicated in adjacent
countries with food security and livelihood characteristics similar to Kenya, such as Ethiopia and
Somalia. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
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Cassava breeding through complementary conventional and participatory approaches in western Kenya.Were, Woyengo Vincent. January 2011 (has links)
Participation of farmers in plant breeding programmes has been reported to increase
breeding efficiency. Farmers’ participation bridges the gap between variety development and
dissemination and provides an opportunity for farmers to select varieties they prefer. The
breeders on the others hand learn more about the farmers’ preferences and the environment
in which the new varieties will be grown. However, the advantages of participatory breeding
can best be realized when farmers’ indigenous technical knowledge (ITK) and experience
complement the breeder’s scientific knowledge and skills. Cassava (Manihot esculenta
Crantz) is a clonally propagated crop grown in diverse environments by small scale farmers
for subsistence. Information on the roles of farmers and breeders at various stages of
breeding and their ability to effectively participate in breeding programmes is limited. The
objectives of this study were to determine: (1) cassava farmers’ preferences, production
constraints and systems; (2) farmers’ selection criteria of cassava varieties; (3) genetic
inheritance of farmer preferred traits; (4) how farmers and breeders complement each other
at all stages and activities of cassava breeding.
Participatory rural appraisal was conducted in three purposefully sampled districts of western
Kenya based on ethnicity and agro-ecology. The results reveal that cassava is
predominantly grown by small scale farmers with mean land size of 1.6 ha mainly under
mixed cropping system for subsistence. The storage roots are eaten either after boiling or
processing to flour. The majority of farmers (over 60%) are aware of the improved varieties
but adoption rate is low (18% in some districts). The effects of pests and diseases, and the
lack of high yielding varieties, capital, land, and disease free planting material are the most
important constraints to cassava production. Farmers prefer tall, high yielding varieties that
are resistant to diseases and pests, early maturing and long underground storability of
harvestable storage roots. The districts surveyed significantly differed in popularity of
utilization methods, traits preferences and relative ranking of the production constraints
indicative of differences in ethnicity and agro-ecology.
Three farmer groups from the three districts selected in western Kenya were used to study
farmers’ variety selection criteria based on their own indigenous technical knowledge (ITK).
The groups evaluated 15 (10 landraces and five improved) popular cassava varieties with
concealed identities on their farms. The results revealed that farmers have effective methods
of selecting varieties for most of their preferred traits. However, ITK alone cannot be used to
evaluate all the important traits, such as cyanide content.
The genetic inheritance of farmer preferred traits was determined through a genetic study.
Six landraces and four improved varieties popular in western Kenya were crossed using the
North Carolina mating design II to generate 24 full-sib families. The 24 families, represented
by 40 siblings each, were evaluated at two sites, Kakamega and Alupe research station
farms, in a 24 x 40 a-lattice design. General combining ability (GCA) and specific combining
ability (SCA) mean squares were significant (P<0.05) for all traits evaluated except dry
matter content and cyanide content. However, non-additive gene action predominated over
additive gene for cassava mosaic disease (CMD) resistance, height to first branching, total
number of storage roots per plant and fresh storage root yield in all environments. The best
crosses were not necessarily obtained from parents with high general combining ability
confirming the presence of non-additive gene action. The best performing parents per se did
not necessarily have high GCA effects implying that selection based on the per se
performance of parents may not always lead to development of superior hybrids.
The clonal evaluation trial (CET) was established at Alupe research station and evaluated by
the breeder and farmers from two districts independently. Three selection criteria were
tested to determine the most appropriate approach to selection of varieties that meet both
farmers’ and breeder’s preferences. The selection criteria were; farmers’ independent
selection index (SI) derived from farmers’ selection criteria from each district, breeder’s
negative selection and independent SI, and a participatory SI which combines farmers’ and
breeder’s selection criteria. There was 14% overlap among the top 100 varieties selected by
farmers from all districts and the breeder when independent SI were used. However, there
was 49% overlap among the top 100 varieties selected by farmers using participatory SI and
the breeder’s SI. The farmers and the breeder have a role to play in the variety development
process. Varieties with traits preferred by both the farmers and the breeder are likely to
enhance breeding efficiency and effectiveness. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
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Participatory-based development of early bulking cassava varieties for the semi-arid areas of Eastern Kenya.Kamau, Joseph Wainaina. January 2006 (has links)
Cassava (Manihot esculenta Crantz) is an important food security crop in the semi-arid
areas of Eastern Kenya. It provides food for more days in a calendar year than any other
crop grown. Kenya has relied on varieties bred in other countries and because of this,
local breeding methodologies and expertise are lacking. Access to appropriate varieties
and adequate planting materials are major limiting factors to cassava production.
Farmers grow late bulking landraces that take up to 18 mo to harvest. Efforts to introduce
early bulking genotypes from IITA failed because of poor end-use quality. Local cassava
breeding is necessary to alleviate the production constraints. Before a local breeding
program can be established, farmers' preferences and production constraints must be
identified and methodology appropriate to the Kenyan environment must be developed.
The aims of this study were to identify farmer production constraints and preferences, to
develop methods appropriate for cassava breeding in the semi-arid areas of Kenya,
develop a population segregating for bulking period to estimate genetic variances that
would explain the gene effects controlling yield components, and through participatory
selection identify varieties that combine early bulking and preferred end-user traits.
PRA tools, focus groups and individual interviews were used to identify production
constraints and farmer preferences for cassava varieties. The PRA found that farmers
grow 13 landraces in the area and 11 production constraints were identified and
prioritised. The four most limiting in the order of importance were drought, lack of
planting material, pests and diseases.
Crosses between cassava varieties often do not produce much seed and the seed
produced does not germinate well. Germination studies were done with open pollinated
seeds to identify conditions favourable for seed germination in Kenya. The highest
germination of the seeds was at 36°C. The control seeds had a higher germination
percent (77%) compared to the seeds which were pre-heated at 36°C (57%).
Crosses were made between selected IITA and local Kenyan genotypes following the
NC 11 mating design to develop new genotypes which combine early bulking along with
other farmer/end-user preferred characteristics. The hybrid progenies were evaluated in
a seedling trial and clone genotypes advanced to a clonal trial and performance trial. The
clonal trial was destroyed by red spider mites and cassava green mites, and only the tolerant 225 genotypes were planted in a performance trial that was harvested at 6, 7
and 8 mo after planting. The SCA effects were estimated to be 57% to 75% for most of
the traits, except root number, which was mainly controlled by GCA effects (55%).
Participatory selection of genotypes that combined early bulking and end-user qualities
at the 7 and 8 mo after planting was done by farmers. Thirty genotypes that combined
early bulking and end-user qualities were identified and ranked according to their
performance in both agronomic and end-use traits using a selection index. A number of
selected genotypes yielded more than three times the yield of the best parents, showing
strong progress in breeding. Combining the farmers' preference aggregate score and the
selection index based on the agronomic data, assisted in the final identification of the
best genotypes developed in the breeding process. These results clearly demonstrated
that it is possible to breed early bulking varieties with good end-use quality in the semiarid
areas. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
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Genetic studies of quantitative and quality traits in rice under low and high soil nitrogen and phosphorous conditions, and a survey of farmer preferences for varieties.Munji, Kimani John. January 2010 (has links)
Rice is an important crop ranking third after maize and wheat in Kenya. Its demand is
growing at 12% per annum, while production has stagnated for quite a number of years.
This situation has lead to consumption outstripping production by about 84%. There is
therefore an urgent need to step up domestic production.
To understand farmers’ preferences, the first survey on rice production was carried out.
To supplement on this survey information, focus group discussions and key informants
were incorporated to further shed more information. The farmers demonstrated their
preferences for varieties that were high yielding, hybrid rice and with high nutrient use
efficiency and these constituted 53.7% of their wishes. Among the crops grown by the
selected farmers, rice was the most important followed by maize, however, the
hectarage of maize was higher followed by rice. The farmers also identified labour costs
as a factor limiting production especially for irrigated rice and thus they preferred upland
rice due to its ease of production. Farmers identified land preparation, inputs, planting,
weeding and harvesting as the most expensive activities. The existing varieties were
viewed as being highly dependent on inputs which they could not afford. The main
fertilizers used were Diammonium Phosphate (DAP), Sulphate of Ammonia (SA),
Calcium Ammonium Nitrate (CAN) and NPK (23:23:0), the amounts used were low even
though the farmers were aware that soil fertility was low.
No studies or attempts had been carried out to determine performance of rice genotypes
and their heritability parameters for adaptation to low soil nitrogen (N) and phosphorous
(P) conditions identified by the farmers as a major constraint in Kenya. Since the existing
genetic base was narrow, accessions were acquired to broaden the variability of the
local cultivars. However, their adaptation to local conditions was important for them to be
useful. Evaluation of 390 accessions showed that genotypes and soil environments were
highly significant for all the ten traits studied. The degree of genetic determination (H(2))
ranged from 8.0% for 1000 grain weight to 27% for top biomass. The phenotypic
coefficient of variation of genotypes ranged from 12% for days to maturity to 149% for
top biomass, while, that of days to maturity ranged from 14% to 160% for top biomass.
The genetic advance (GA) had values ranging from, 0.2 for phosphorous tolerance to
1081 for grain yield, while the genetic advance expressed as percent of the mean was
6% for days to maturity and 88% for top biomass. The mean values for the ten
characters studied had wide variability under the four soil environments with days to
maturity ranging from 188 for genotype ARCCU1Fa1-L4P3-HB under both N and P
application (N+P+) to 177 for genotype CT16333(1)-CA-1-M under none N and P
application (N-P-) condition. The highest yielding genotype was CT16328-CA-18-M
under none N and P application with 5916 kg ha(-1). The germplasm revealed usable
variability under low soil N and P adaptation and thus warrant rice improvement for traits
of interest to farmers.
In order to establish the genetic factors controlling upland rice adaptation to contrasting
soil N and P a study was conducted to determine genotypes with better performance
under the prevailing farmers’ production environments. The GCA and SCA mean
squares were significant and their interactions with environment were highly significant.
The GCA:SCA ratios were mostly less than 1.0 for the majority of the traits under most of
the soil N and P environments, indicating preponderance of nonadditive genetic effects.
The maternal and nonmaternal mean squares were significantly different from zero
(P<0.05) for most of the ten traits under study, indicating influence of cytoplasm effects and cytoplasm by nuclear gene interactions, respectively. The GCA effects for the
parents were significant under different experimental environments but they had both
positive and negative signs indicating different directions of influencing the trait of
interest. The genotypes had both specific and broad adaptation as exhibited by their
diverse rankings under different environments.
The relationship between leaf and grain nitrogen (N) and phosphorous (P) with actual
tolerance to low and high soil N and P conditions indicated significant genotypes,
environments and genotypes by environment interactions. The analysis of genetic
components gave highly significant GCA and SCA mean squares for the days to
heading, anthesis and maturity, phosphorous and nitrogen tolerance, top biomass, plant
height, number of panicles, 1000 seed weight and grain yield under the four soil
experimental environments. The general combining ability (GCA) effects for parents
were significant for both F(2) and F(3) segregants for the above ten traits and under the
experimental conditions. The leaf and seed N and P contents gave significant genotype
mean squares values for the three mega-environments. The GCA and SCA mean
squares were significant for leaf and seed N and P for the three locations. The same
case was observed for GCA effects for the parents, with all the nine parents showing
significant values for leaf N and P for the three locations. The GCA:SCA mean square
ratios were generally larger than 1.0 values for leaf N and grain P for the three locations.
This clearly manifested the predominant role of additive gene action over the dominance
effects and that improvement for tolerance to low soil N and P condition was practical.
The fragrance in rice is an important quality traits and an experiment was conducted to
establish the association of organoleptic test and the variations in SSR marker (RM223)
among the parents. Plant leaves of the parental genotypes were sampled for DNA
analysis using SSR markers RM223 and RM284. The RM223 was polymorphic while,
RM284 gave monomorphic results. Four alleles were detected as follows: 146, 155, 161,
and 163. The GCA:SCA ratio was 1.48 indicating that the fixable additive effects were
greater than the nonadditive effects in inheritance of fragrance. Test for independence
using Chi-square indicated that there was no association between organoleptic and
variations in SSR markers. The performance of the aromatic lines was generally lower
than that of non-aromatic lines for the agronomic traits. There was negative relationship
between fragrant score and other agronomic traits such as grain yield across the three
soil N and P regimes. The NERICA1 was found to be a good donor for aroma based on
sensory testing and can be exploited in a breeding programme.
Analysis on genetic components governing grain yield was investigated using Hayman’s
analysis to generate various components of variation and to elucidate their potential,
utilization, and provide a thorough understanding of their role in grain yield development
and improvement. The additive gene action was significant for all cases of soil N and P
environments and the two mega-environments. They were also far above the dominant
gene effects, indicating the need to use mass selection in the early generations of
segregating populations. The narrow sense heritability (h2(ns))
for upland rice grain yield
was 21.52% and 4.22% under soil P and N conditions, respectively. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
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Genetic analyses for resistance to soybean rust (Phakopsora pachyrhiz) and yield stability among soybean genotypes in Kenya.Wanderi, Susan Wothaya. 31 October 2013 (has links)
Soybean (Glycine max (L.) Merr.) occupies an important position in the world economy of the feedstock of high quality protein and vegetable oils. However, its production is threatened by, Asian soybean rust (ASR), caused by the rust fungus Phakopsora pachyrhizi Syd. & P. Syd. This fungus is highly dependent on environmental conditions, has a wide range of hosts, and evolves rapidly into novel races, making it difficult to control. In addition, most commercial varieties are susceptible to rust, the rust has already developed resistance to triazole fungicides, and most small-scale farmers cannot afford expensive systemic fungicides to control the
disease. The use of resistant varieties is the most viable, long-term option to manage ASR, especially in the small-holder soybean farming sector. This study was therefore designed to undertake the following goals: (i) to identify farmers’ preferred varieties and desired traits, their knowledge of ASR, and other key constraints affecting soybean production in Kenya; (ii) to
evaluate soybean accessions for rust resistance, and to determine the correlation of rust resistance with other agronomic traits; (iii) to determine the mode of inheritance for ASR resistance and selected agronomic traits; and (iv) to determine yield stability of soybean advanced lines at multiple sites in Central and Eastern Kenya. To understand farmers’ preferred varietal characteristics, knowledge of ASR and other key constraints to soybean production, a survey was conducted using a structured questionnaire in the major soybean growing areas of Kenya. The farmers preferred local varieties because of their desirable characteristics, which included high yields, early maturity, drought tolerance and seed availability. Although the majority of the participating farmers expressed a willingness to grow improved varieties, financial limitations, seed unavailability and lack of information were the major barriers to their use of improved varieties. High yield, early maturity, adaptability and grain quality were the traits that most farmers sought in an ideal soybean variety. Knowledge of the cause of ASR was limited, and its occurrence was largely attributed to environmental factors, poor soil fertility conditions, poor agronomic practices, physiological maturity and specific species of weeds. Their investments in control methods were minimal due to a lack of technical knowledge, poor access to fungicides, and limited resources. Other constraints faced by soybean farmers included: lack of access to grain markets; lack of knowledge in processing and utilization of soybean grain; the unavailability of seeds; losses to pests and diseases; the lack of inputs such as fertilizers; frequent dry spells; and low yielding varieties. A total of 110 soybean accessions were evaluated for their rust reactions and correlations with selected agronomic traits. These included plant introductions possessing single rust resistant genes (Rpp1-4), tolerant lines, gene bank accessions, commercial varieties and advanced lines.
Soybean genotypes varied significantly in their reactions to rust severity, sporulation, lesion type and area under disease progress curve (AUDPC) values. Genotypes possessing Rpp4 (G10428) and Rpp2 (G8586) resistant genes, and non-characterized genotypes MAK BLD 11.3, GC 00138-29 and Namsoy 4M, were the most resistant accessions, as indicated by low rust
severity scores, low AUDPC values, red brown lesions and low sporulation scores. Other genotypes with known resistant genes including G7955 (Rpp3), G58 and Tainung 4 (Rpp1), a few tolerant lines, and one advanced line (BRS Sambaiba) were moderately resistant. All the other advanced lines, commercial varieties, gene bank accessions and collections from the
farmers’ fields were highly susceptible to rust. Rust severity was positively correlated with rust sporulation, indicating that reduction of sporulation made a significant contribution towards rust resistance. An F2 population was generated from a half diallel mating design, involving 4 resistant, 2
moderately resistant and 2 susceptible genotypes selected as parents. The F2 populations along with their parents were evaluated in two environments to determine the type of gene action for rust resistance and other quantitative traits in soybeans. The results revealed that both general combining ability (GCA) and specific combining ability (SCA) were significant for most of the traits studied, indicating that both additive gene action and non-additive gene action played a major role in the inheritance of rust resistance and selected agronomic traits. The GCA/SCA ratio was close to unity for rust severity, rust sporulation, days to flowering, days to
maturity and plant height. This indicated that additive gene action played a more significant role in the inheritance of these traits than non-additive gene action. Non-additive gene action was only predominant for soybean grain yield. Parental lines G10428, G8586 and Namsoy 4M were the best general combiners for improving rust resistance across the environments. The most promising parents for early flowering were G7955, G8586 and G58. Parent Maksoy 1N was the
best general combiner for early maturity while parents Maksoy 1N, G58, G7955 and Nyala contributed effectively towards reduced plant height.
Yield stability analysis was conducted for 30 genotypes in 6 environments, using additive main effects and multiplicative interaction (AMMI), genotype main effect and genotype x environment interaction (GGE) biplot analyses. Genotypes 916/5/19 and G7955 were identified as the high yielding and most stable across the environments. On the other hand, genotypes BRS MG46 and Sable were high yielding but unstable and specifically suitable for the environments EM2 and MW2, respectively (both environments have long rainy seasons). Environment EM2 was identified as the most discriminating and representative among the six environments.
Environments IG1 and MW1 (short rainy seasons) were less informative on genotypes tested, as confirmed by short environment vectors. Environment EM1 was better for discriminating genotypes but was a poor representative of the test environments, hence it should only be
utilized for developing specifically adapted genotypes. Further analysis using GGE biplot approach grouped the environments into three putative mega-environments in Central and Eastern Kenya. Overall, this study established the need to educate farmers on the cause of ASR, to develop
ASR resistant varieties, and to incorporate farmers’ desired traits in the breeding programme, especially by the use of participatory breeding approaches. The resistant and moderately resistant genotypes identified in this study could be used as sources of resistant genes to develop ASR resistant varieties in Kenya. This study also established that genetic improvement for ASR resistance and selected agronomic traits in soybeans is possible based on the use of recurrent selection breeding procedures that result in the accumulation of additive gene effects. Selection of late segregating generations would be effective for soybean grain yield
improvement. This study identified potential parents for ASR resistance and selected agronomic traits, but they require further breeding to improve on farmers’ desired traits. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
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