Journal Articles
http://41.89.164.27:8080/xmlui/handle/123456789/301
2024-03-28T10:07:20ZIDENTIFICATION OF DROUGHT TOLERANT KENYAN BRACHIARIA ECOTYPES USING DROUGHT TOLERANCE INDICES
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.
2023-06-01T00:00:00ZDiscovery 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
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.
2023-10-01T00:00:00ZEvaluation of Proximate and Mineral Composition of Mutant Dolichos Lablab (Lablab purpureus L.) Accessions in Kenya
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.
2021-08-01T00:00:00ZCharacterization of effect of Gamma ray on morpho-Agronomic traits of dolichos Lablab (Lablabpurpureus I.) sweet
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
2021-09-01T00:00:00ZGenetic Variability, Heritability and Genetic Advance of Yield and Yield Contributing Characters in Putative M2 Dolichos Bean (Lablab purpureus L.) Accessions
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.
2023-03-01T00:00:00ZEvaluation of the Effectiveness of Drying Groundnuts (Arachis hypogaea) on Post-Harvest Losses: A Case Study of Khwisero Sub-County, Kenya
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.
2022-06-01T00:00:00ZSesame Production Characteristics and Challenges in Western Kenya
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
2022-06-01T00:00:00ZCharacterization of Honey from Marigat in Baringo County, Kenya, based on their Physical Properties
http://41.89.164.27:8080/xmlui/handle/123456789/1528
Characterization of Honey from Marigat in Baringo County, Kenya, based on their Physical Properties
Chepkemoi, Mercy; Kollongei, J.; Some, D.
Marigat in Baringo County is among the Arid and Semi-arid Lands (ASAL) in Kenya where
apiculture is the main source of income. Honey producers in the area keep their bees in the
indigenous hives and natural colonies. Traditional methods are mainly used to harvest and
process honey in the area. Honeycombs are crushed and mashed with bare hands to produce
honey which is very unhygienic and not fit for human consumption. Honey produced by this
method is of low quality hence sold in the local markets at a very low price. This contributes
to high poverty levels and low living standards of honey producers residing in the area.
However, this paper aims at characterizing honey based on its physical properties. These
properties are significant in providing information regarding the quality of honey harvested
from different locations of Marigat. This paper presents the physical properties of twelve (12)
samples of honey collected from various locations of Marigat. The locations were Maoi
Centre, Lopoi Junction, Marigat Town, and Koriema Centre. Honey samples from these
locations were analysed based on their physical properties to determine the quality of honey
produced in the area. The physical properties were moisture content, pH, relative density, and
total water-insoluble solids content. Values of these parameters were compared with those of
the set standards and requirements by the Kenya Bureau of Standards (KEBS) in Kisumu
County. Results showed mean parameter values of moisture content, pH, relative density and
total water-insoluble solids content of 18.05%, 3.9, 1.41 g/ml, and 0.22% m/m respectively.
The range values of these parameters were 17.1% to 19.6%, 3.3 to 4.2, 1.4045 g/ml to 1.4343
g/ml, and 0.07% m/m to 0.61% m/m respectively. Moisture content and total water-insoluble
solids content values of honey samples were within the maximum requirements of 22% and
0.5% m/m respectively as set by KEBS. However, results obtained from some locations for
moisture content were not within the range of 14 to 18% as set by International Honey
Commission (IHC) and Codex Alimentarius Commission (CAC). The total water-insoluble
solids content of honey proved that honey was extracted by using the traditional method. The
relative density of honey was slightly lower and higher than the set permitted limit of 1.42
g/ml, showing that moisture content in honey may be present in some locations. The pH values
of honey were observed to be slightly higher and lower in some locations than the
recommended value of 3.9. Hence, determining the quality of honey would ensure honey
produced meets both local and international standards. This will attract higher profits and
increased production rates. Hence, improving the standards of living of honey producers
living in the area due to increased income from the sale of honey.
2021-01-01T00:00:00ZGenetic diversity of elite wheat mutant lines using morphological characters and molecular markers
http://41.89.164.27:8080/xmlui/handle/123456789/1367
Genetic diversity of elite wheat mutant lines using morphological characters and molecular markers
Chemwok, Philip K.; et al.
Genetic diversity is the material basis for crop improvement. The genetic diversity of 17 wheat
genotypes was evaluated using 25 agro-morphological characters and 10 simple sequence repeat (SSR)
markers. The objective of this study was to determine the genetic diversity of elite stem rust resistant
mutant lines in comparison with their adaptable but susceptible parent varieties using morphological
traits and molecular markers. The results obtained showed significant variation in morphological traits
and molecular makers existed. Morphological diversity between mutant lines and their parent varieties
was mainly separated by grain yield per spike, 1000 grain weight and maturity time period. The
dendrogram based on 10 SSR markers grouped the 17 genotypes into three major clusters and six subclusters
with mutants clustering with their respective parents. 10 SSR primer pairs yielded 13
polymorphic loci with a percentage of 92.86%. The mean number of alleles per locus in each group was
2.0 and the mean number of polymorphic alleles per locus was 1.9286. The gene diversity ranged from 0
to 0.4893 for each sample. Results showed it is possible to classify genetic diversity of elite wheat
genotypes and select them for the highest genetic diversity. The results can be used in selecting
diverse parents in breeding programs and also in maintaining genetic variation in the germplasm.
2019-09-01T00:00:00ZEffect Of Gamma Irradiation Mutagenesis On Diversity Of Cassava Tissue Culture Plantlets
http://41.89.164.27:8080/xmlui/handle/123456789/1359
Effect Of Gamma Irradiation Mutagenesis On Diversity Of Cassava Tissue Culture Plantlets
Kinyua, M. G.; Okwaro, H.
Cassava, Manihot esculenta Crantz (Euphorbiaceae), is one of the leading food and feed plants of the world and stands as the 3rd largest source of carbohydrates for human consumption after rice and maize. However, the cassava sub-sector has not realized its full growth in terms of commercialization and utilization. It is evidenced that the tuber crop can enhance the food base of the poor, increase their income and mitigate poverty among rural households but challenge of diseases and pest hamper its performance. Mutation and efficiency enhancing techniques have been shown to improve resistance in crops through increased diversity from which desired selections can be made. This study was aimed at development of tissue culture generated mutant populations of cassava mosaic virus (CMV) resistant cassava through gamma irradiation and in-vitro selection. Tissue cultured plantlets of farmer and consumer preferred but CMV susceptible cassava variety KM-1 were irradiated with gamma rays at 15Gy and the mutagenised population subcultured 4 times to M1V3 to eliminate chimera. Selected putative mutants were screened for effect of mutagenesis, in comparison with the parent variety. The assessed parameters included plant height through the first growth period, number of nodes, leaf morphology (number of leaf lobes) and colour of petiole. The data was collected after every fortnight for 2 months. Results showed that the mutant selections differred among themselves as well as from the parent variety in the assessed paramenters. The lobes for the parent variety were 5 while for the mutant population these raged from 4 to 9 and the differences were found to be significant. There was no significant difference in the petiole colours
2021-02-01T00:00:00Z