http://41.89.164.27:8080/xmlui/handle/123456789/301 2026-04-07T19:42:43Z http://41.89.164.27:8080/xmlui/handle/123456789/2551 INFLUENCE OF ENVIRONMENT AND ITS INTERACTION EFFECTSON NEW POTATO [(Solanum tuberosum (L.)] MUTANT LINES Muasya, Mutati; Kinyua, Miriam; Chepkoech, Emmy 2025-06-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/2449 Hybrid Performance, Heritability and Trait Associations in Yellow Maize (Zea mays L) Inbred Lines Shiundu, Daniel W.; Pkania, Kennedy; Chepkoech, Emmy The challenge of decreasing maize yields in Kenya and Sub-Saharan Africa due to biotic and abiotic stresses is further compounded by limited supply of improved hybrid varieties. This study aimed to evaluate the hybrid performance, heritability and examine phenotypic correlations between grain yield and yield-related traits in yellow maize inbred lines in Western Kenya. One hundred and thirty F1 testcrosses produced using a line-by-tester mating design of two-line testers on 65 yellow lines were evaluated across three locations using a 7×19 alpha lattice with two replications. Phenotypic data on grain yield and yield related traits were used to compute best linear unbiased estimates of means and variance components in META-R while R package ‘corrplot’ computed phenotypic correlations. Significant (p=0.001) genotypic and genotype-by-environment variances were observed for grain yield and related traits, except for plant height which did not show significant genotypic variance. With a trial mean of 9T/Ha and an LSD0.05 1.7, the testcross L45×TA produced the highest grain yield across sites at 12.4T/Ha. Studied traits showed high heritability across sites, with the exception of the Northern leaf blight, which had moderate heritability (46%). Significant phenotypic correlations were found between traits, with ear height showing the highest positive correlation with grain yield (r = 0.67, p=0.001). With higher genotypic variance than genotype-by-environment interaction variance, high heritability for grain yield and related traits and significant correlations between them, this germplasm offers opportunities for both direct and indirect selection in maize breeding programs aimed at yield improvement since most of the measured traits are largely dependent on the genetic value of the germplasm. 2025-01-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/2432 Agro-Morphological Characterization and Diversity Analysis of Selected Sorghum Genotypes in Kenyan Agro-Ecologies Rutto, Emmah Cheluget; et. al... Sorghum (Sorghum bicolor) is a very important cereal crop cultivated globally, primarily in arid and semi-arid regions. It ranks fifth among the most important cereal crops globally, after wheat, rice, maize, and barley. Despite its crucial role in food security and climate resilience in arid and semiarid regions, sorghum production remains suboptimal, with yields consistently falling below the crop’s genetic potential. Understanding its morphological diversity is essential for effective breeding programs and genetic resource conservation. This study aimed to determine valuable morphological variation among selected sorghum genotypes against released varieties using a diverse set of traits and their correlations. The experiment was laid out using a Randomised Complete Block Design with three replications using 13 genotypes sourced from the University of Eldoret, and 03 checks from the Kenya Seed Company in Kenya. The genotypes were grown in Endebess and Sigor for one season and evaluated based on morphological traits. Using GenStat statistical software 14th Edition, data on qualitative and quantitative traits were analysed at 5% level of significance. The significant differences among the sorghum genotypes were tested using analysis of variance (ANOVA). Correlation Matrices, first, second and third principal component (PCA) were performed. Principal component analysis revealed the three most important PCs that contributed 81.78%, 15.33% and 1.5% of the total variation, respectively. At the Endebess site, grain yield exhibited the highest genotypic variation among the evaluated sorghum genotypes. E1291 recorded the longest leaves (67.87 cm), whereas Kalatur exhibited the shortest (36.13 cm). Moreover, mean comparisons between the two environments showed that Sigor recorded a higher mean grain yield (2.01 t ha⁻¹) compared to Elgon Downs (1.73 t ha⁻¹). Plant height (0.889) was the trait that contributed most to the variation in the first PC. Number of days to harst (0.814) contributed most to the variation in the second PC, whereas leaf length (0.842) was the largest contributor to the variation observed in the third PC. Correlation analysis showed significant positive relationships between 50% days to emergence to 50% days to flowering and days to maturity (r=0.7 and r=0.9), respectively, suggesting that these traits can be used as selection criteria in breeding programs. The frequency distribution analysis indicated a high occurrence of pigmented leaves (93.75%) and brown grain colour (68.75%), reflecting the natural variability within the studied population. The phenotypic evaluation of sixteen sorghum genotypes revealed significant agro-morphological diversity, confirming the genetic variability. These findings support informed selection and genetic improvement to boost yield and stress resilience in sorghum breeding for Kenya and similar regions. 2025-01-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/2101 IDENTIFICATION OF DROUGHT TOLERANT KENYAN BRACHIARIA ECOTYPES USING DROUGHT TOLERANCE INDICES Awalla, B. J.; Were, B. A; Binnot, J. Drought is one of the major abiotic stress factors limiting agricultural productivity globally. Brachiaria also known as signal grass is a native of sub-tropical and tropical Africa and important in livestock production. The grass has many advantages including; high biomass, high nutritional value, adaptation to drought and low fertility soils, sequestration of carbon, enhanced nitrogen uses efficiency and low greenhouse gas emissions. Emergence of climate change with increased global temperatures has led to prolonged drought which has adversely affected the improved Brachiaria hybrids. Locally available ecotypes are a rich source of unique genes and characteristics that could be key in developing drought resilient hybrids. The objectives of this study were to i) assess the effectiveness of various indices in selection of drought tolerant Kenyan Brachiaria ecotypes, ii) evaluate the relationship between the indices and iii) to identify high yielding and stable ecotypes under stressed condition. The design of the experiment was completely randomized design (CRD) with three replications in a factorial arrangement (3 x 25). A total of 11drought tolerance indices; tolerance (TOL), stress Tolerance Index (STI), mean productivity (MP), yield stability index (YSI), Geometric Mean Productivity (GMP), stress susceptibility index (SSI), Yield Index (YI), harmonic Mean (HM), drought intensity index (DII), modified stress tolerance k1 and modified stress tolerance k2 were calculated based on shoot biomass production under non-stressed (YP) and stressed (YS) conditions. Rank means, rank sum and standard deviation were also used to identify the tolerant materials. In the previous experiment, various physiological parameters were scored which included; leaf relative water content, relative chlorophyll content using SPAD -502 Chlorophyll meter (Minota Co), leaf fresh weight, leaf dry weight and leaf relative water content. Relative water content was also estimated and comparative scores were done between control, medium and extreme or water deficit experiments. Based on all the indices and ranking, BrK 1, BrK 6, BrK 7, BrK13 and BrK 18 were the most tolerant in stressed condition. These ecotypes can be recommended for planting in areas prone to drought. More studies on the identified tolerant ecotypes are essential to ascertain whether the materials hold unique genes that could later be introgressed into various breeding schemes to confer tolerance. 2023-06-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/2091 Discovery of genomic regions associated with grain yield and agronomic traits in Bi-parental populations of maize (Zea mays. L) Under optimum and low nitrogen conditions Kimutai, Collins; et al. Low soil nitrogen levels, compounded by the high costs associated with nitrogen supplementation through fertilizers, significantly contribute to food insecurity, malnutrition, and rural poverty in maize-dependent smallholder communities of sub-Saharan Africa (SSA). The discovery of genomic regions associated with low nitrogen tolerance in maize can enhance selection efficiency and facilitate the development of improved varieties. To elucidate the genetic architecture of grain yield (GY) and its associated traits (anthesis-silking interval (ASI), anthesis date (AD), plant height (PH), ear position (EPO), and ear height (EH)) under different soil nitrogen regimes, four F3 maize populations were evaluated in Kenya and Zimbabwe. GY and all the traits evaluated showed significant genotypic variance and moderate heritability under both optimum and low nitrogen stress conditions. A total of 91 quantitative trait loci (QTL) related to GY (11) and other secondary traits (AD (26), PH (19), EH (24), EPO (7) and ASI (4)) were detected. Under low soil nitrogen conditions, PH and ASI had the highest number of QTLs. Furthermore, some common QTLs were identified between secondary traits under both nitrogen regimes. These QTLs are of significant value for further validation and possible rapid introgression into maize populations using markerassisted selection. Identification of many QTL with minor effects indicates genomic selection (GS) is more appropriate for their improvement. Genomic prediction within each population revealed low to moderately high accuracy under optimum and low soil N stress management. However, the accuracies were higher for GY, PH and EH under optimum compared to low soil N stress. Our findings indicate that genetic gain can be improved in maize breeding for low N stress tolerance by using GS. 2023-10-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/1973 Evaluation of Proximate and Mineral Composition of Mutant Dolichos Lablab (Lablab purpureus L.) Accessions in Kenya Kimno, S. K.; et al. Plant breeding through induced mutation technology is a potent method to creating new variants of food crops with of desirable phenotypic, genetic and biochemical functions. It is a catalyst in developing improved crop varieties where classical hybridization or selection have limitations. It has been used to improve nutrition quality and higher yield in a number of legumes. Dolichos Lablab (Lablab purpureus L) is multipurpose legume that has not been exploited extensively for food nutritional properties through breeding. The purpose of the study was, therefore, to generate awareness that nutritional status of D. Lablab could be improved through mutation induction and be a good source of food components essential for good health. Twenty-four dolichos Lablab germplasms including 20 mutant accessions and 4 commercial genotypes were evaluated for proximate values and mineral contents in Kenya in 2021 based on Association of Official Analytical Chemists (AOAC). Data analysis was based on least significant difference (P = .05).The revealed percent moisture, ash crude fat, crude fibre, crude proteins and total starch content ranged : 7.35% -11.84%, 1.09 -2.90%, 3.35% - 8.05% , 8.86 - 12.70% , 20.03% - 28.87% and 25.50% - 39.00% .The mineral content of phosphorous (P), potassium(K) and calcium (Ca) ranged from 27mg - 57mg, 132mg -297mg and 7mg - 19mg. A significant positive correlation between ash levels to P and K concentration and on P to K concentration. The result of analysis ranked 9 (WT026, WT018 ,MT110 , BT188 , BT032, BT114, MT076 BT137,GT09) different accessions that positively contributed to the nutritional content of the investigated dolichos lablab accessions. Further research on the superior accessions can be done on yield potential, resistance to biotic and abiotic constrains, sensory preferences or used in bio fortification of existing genotypes. 2021-08-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/1970 Characterization of effect of Gamma ray on morpho-Agronomic traits of dolichos Lablab (Lablabpurpureus I.) sweet Kimno, S. K.; et al. Lablab purpureus (L.) Synonym Dolichos lablab (L.) Sweet; is a minor and an important multipurpose legume. Despite this it classified as an orphaned crop hence few studies on its improvement have been undertaken. Limited studies have been carried out on use of mutation on dolichos improvement. Four elite Lablab genotypes coded G1, B1, M5 and W7 were mutagenized with two doses of gamma radiation 300Gy and 400 Gy with objective to study the effect of mutation on various agronomical traits at M2 generation. Data on effect of irradiation on lablab was collected 10 randomly selected plants of on each plot .The traits evaluated were leaf length, leaf width, number of raceme per plant, raceme length, pod length, pod width, plant height, dry seed yield per plant and seed length and seed width. For these traits mean of mutant plants was significantly different from mean of control plants at P≤0.05. Mutant accessions of B1, M5 and W7 genotypes exhibited wide mutation spectra after mutagenesis of albino, leafiness, upright single stem, seedless pod, short dwarf pod, variegated leaf, variation in flower colour, variation in growth habit, leaf shape, seed colour. Gamma irradiation doses of 300 Gy and 400 Gy were potent in mutagenesis of the studied dolichos lablab. The agronomically diverse mutants are an important resource for dolichos improvement through breeding and genetic studies. Mutants with variegated leafs and flower colour can be used in the landscaping while those different seed colour could be used in the improvement of sensory and cooking qualities of other native dolichos lablab beans 2021-09-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/1963 Genetic Variability, Heritability and Genetic Advance of Yield and Yield Contributing Characters in Putative M2 Dolichos Bean (Lablab purpureus L.) Accessions Kimno, S. K.; et al. Dolichos bean (Lablab purpureus L.) is a multipurpose, orphan leguminous crop in Kenya .It is characterized with narrow genetic diversity and low yield output. Use of nuclear techniques such as gamma ray induction in breeding for improved genetic variability is an effective approach in improvement of this important crop. Studies on genetic variability estimates of two Kenyan dolichos bean accessions were undertaken as the pre-requisites for selection of potential high yielding putative accessions for production. This study was conducted between May 2020 and October 2020 at biotechnology department, University of Eldoret research field, Kenya. 0gy, 300gy and 400gy mutant accessions of Eldo maridadi and Eldo black I respectively were raised in Randomized Complete Block Design (RCBD) with three replications. Data was collected either on plot basis or from randomly taken 3 plants on days to 50% flowering, leaf length, number of flower buds per race , raceme length (cm) , plant height (cm), number of nodes per raceme , pod length (cm), 100 seed weight (g), dry seed yield (g). The data collected for each quantitative trait was subjected to analysis of variance (ANOVA) for simple lattice design. There was high PCV and GCV coupled with high heritability in, raceme length (cm), plant height (cm), number of nodes per raceme, pod length (cm), 100 seed weight (g), dry seed yield per plant (g) in Eldo black I accession traits than in Eldo maridadi .The different accession following mutation did exhibit difference in trend of genetic variability estimates. An indication of genotypic differences, response to mutation, lesser influence of environment in expression of the traits, prevalence of additive gene action in their inheritance and amenability of the traits to simple selection. Eldo maridadi accessions exhibited high to low heritability with low genotypic advance as percent of mean in evaluated traits thus direct selection on this traits may not beneficial. Other traits or further improvements on yield potentiality and yield traits on the accessions of this genotype are suggested by creating variation and selection. 2023-03-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/1669 Evaluation of the Effectiveness of Drying Groundnuts (Arachis hypogaea) on Post-Harvest Losses: A Case Study of Khwisero Sub-County, Kenya Kirui, S. K.; Some, D. K.; Mutai, E. B. K. Loss of grains through mould infection is a serious problem for farmers in rural societies. Solar drying of groundnuts offers a huge potential to reduce Aflatoxin contamination. The purpose of this study was to assess the effectiveness of drying groundnuts on post-harvest losses in Kenya. The investigation was guided by the following specific objectives: To characterize the physical characteristics of various groundnut varieties in Khwisero Sub-County, Kenya; to characterize the drying technologies existing in the Sub-County, Kenya and to evaluate the performance of the existing drying technologies in the Sub-County. The study adopted a factorial experimental design. In this study parameters included; temperature, relative humidity, moisture content, drying time, and drying rate. The groundnuts for experimental purposes were acquired through purposive sampling. Data was collected using data loggers, a data sheet, and a household survey. The following physical properties of groundnut grains were evaluated; surface area, bulk density, and porosity. To evaluate the efficiency of the existing dryer designs for effective drying of groundnuts, the effectiveness of each drier was determined the following parameters; drying time, drying rate, moisture content, temperature, and relative humidity. The drying technologies under study were open sun drying, the greenhouse effect, and the modified greenhouse effect. The open sun drying depended on the natural weather while the Greenhouse and the modified greenhouse effect offered the opportunity for the farmers to dry their kernels in any circumstance of weather or duration e.g. sunny, rainy, or cloudy weather, in the day or at night when temperatures are colder with energy reaching the surface of 678 kWh/m2. It is critical to dry harvested groundnuts correctly, as improper drying can promote fungal growth and reduce kernel quality for consumption and propagation. 2022-06-01T00:00:00Z http://41.89.164.27:8080/xmlui/handle/123456789/1648 Sesame Production Characteristics and Challenges in Western Kenya Koitilio, B.; et. al... Sesame is one of the most important oilseed crops in the tropical and subtropical regions of the world. Despite its importance, sesame yield potential in Kenya is very low. The objective of this study was to identify constraints limiting sesame production in Western Kenya. A survey was undertaken in Busia, Bungoma and Siaya Counties of Western Kenya involving a representative sample of 153 sesame farmers. To identify the sampling units, a three-phase stratified sampling was used to select the three counties out of the 10 counties in western Kenya, followed by selection of smaller sampling units from the selected counties. Subsequently, snowball sampling was used to identify the 153 respondent sesame farmers in the selected sampling units. The sampled farmers were then interviewed using a structured questionnaire. The data obtained was analysed using Statistical Package for Social Scientists (SPSS) version 20. The findings showed that majority of sesame farmers were aged above 41years at 66%. Among the respondents, 39% were male while 61% were female. Adult females at 56% mainly provided sesame farming labour. On land tenure, 62% of the respondents inherited land from their parents. The largest proportion (67%) of the respondents obtained seed from the grain markets whereas a majority of the respondents (80%) planted sesame as a mono-crop, in rows (69%) and did not use any fertilizer (81%) in producing their crop. Farmers did not grow any improved sesame cultivars with three popular genotypes being grown that included Local white, Sudan cultivar (advanced) and Local Brown. Pests and diseases were a minor problem in sesame production in the study area. About 70% of the farmers planted sesame for both subsistence and commercial purposes. The majority of the farmers reported yields that ranged between 200 – 400 kg/ha which is still low as compared to yields realized in other regions. There is therefore need to train farmers in this region on the adoption of sesame improved agronomic practices and value addition. Moreover, there is need for all the stakeholders to develop proactive interventions aimed at improving sesame production for food security and increased earnings 2022-06-01T00:00:00Z