Browsing by Author "Karanja, D.R."
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Item Diversity and Population Structure of Local and Exotic Lablab Purpureus Accessions in Kenya as Revealed by Microsatellite Markers(eSciPub LLC, 2021) Kamau, E.M.; Kinyua, M.G.; Waturu, C.N.; Kiplagat, O.; Wanjala, B.W.; Kariba, R.K.; Karanja, D.R.; Kenya Agriculture and Livestock Research Organization ; University of Eldoret ; World AgroforestryLablab purpureus is an important pulse crop in some parts of sub-Saharan Africa and Asia but has largely remained underuti-lized. Understanding the genetic diversity is prerequisite for ge-netic improvement and utilization of this leguminous crop. The relationships of the local lablab genotypes and those collected from other diverse geographic origins including the wild acces-sions remain unknown in Kenya. The study was undertaken to determine genetic diversity and population structure of germ-plasm accessions collected from Kenya and other global regions. Eight simple sequence repeat primer pairs were used to genotype the 189 lablab accessions. A total of 39 alleles were re-vealed by eight SSR with an average of 4.88 alleles per polymor-phic loci. The average PIC was 0.42. The gene diversity among the accessions ranged from 0.26 to 0.52 with an average of 0.38, indicating moderate genetic diversity. Germplasm collected from Kenya showed a moderate genetic diversity of 0.36. Higher ge-netic diversity (He<0.5) was detected within the Ethiopian and South Africa populations. Analysis of molecular variance (AMO-VA) revealed that 94% of the allele diversity was attributed to in-dividuals within populations while only 6% was distributed among the populations. The Bayesian model-based Structure method and Principal coordinate analysis (PCoA) scatter plot clustered the accessions into three groups with germplasms collected from Kenya showing distribution among all the three groups. The wild accessions clustered mainly with those from Southern and Eastern Africa confirming earlier suggestions that lablab is of Af-rican origin. The results of this study are discussed in light of the crop improvement of this crop.Item Enhancing Sorghum Production and Marketing in Semi-Arid Kenya(Kenya Agricultural and Livestock Research Organization, 2014) Karanja, D.R.; Kisilu, R.K.; Kathuli, P.; Mutisya, D.L.; Njaimwe, A.N.; Keya, G.; Ouda, J.; Ayemba, J.; Kenya Agricultural and Livestock Research OrganizationSorghum is an important food security crop especially in semi-arid lands of Kenya. It is adapted in a wide ago-ecological zones. Sorghum requires less water than maize thus offering great potential for supplementing food and feed resources. Although sorghum varieties with a yield potential of 2 to 5t/ha are available, their productivity has remained low, at 0.7t/ ha. The major constraints to sorghum production are: inadequate soil moisture, low soil fertility, bird damage, pests and diseases, high cost of inputs, low adoption of improved varieties, weeds, lack of markets and limited utilization options. Farmers consider lack of markets, low producer prices and bird damage as the main constraints to increased sorghum production. Most sorghum is grown at altitudes of less than 1500 m above sea level. However there are varieties suitable for up to 2400 m a.s.l. It requires a rainfall of 250-400 mm during the growing season. Most dry land sorghum cultivars are those that thrive best in areas with a small range of diurnal temperatures i.e. the day and night temperatures do not differ greatly. Sorghum does best in wide range of soils including sandy, clay and loamy ones. It thrives well on fertile soils but will grow on somewhat exhausted soils.Item Genotypic Variability, Heritability and Path Analysis of Yield Components of Determinate Lablab (Lablab Purpureus (L.) Sweet) Inbred Lines in Kenya(2021-10) Kamau, E.M.; Kinyua, M.G.; Waturu, C.N.; Karanja, D.R.; Kenya Agriculture and Livestock Research Organization ; University of EldoretLablab is a leguminous crop that offers great potential as food and cash crop in Kenya. However, high yielding early maturing determinate varieties suitable for short season environments and for intercropping systems are lacking. This study was conducted to estimate heritability, genetic advance and correlation between grain yields and yield attributing traits of advanced inbred determinate lines. Thirty nine lablab F5 inbred lines and a local determinate accession were evaluated at KALRO Katumani and Thika using randomized complete block design (RCBD) with two replications in 2017. Significant differences (P< 0.05) were observed among the genotypes for all the characters. Phenotypic coefficient of variability (PCV) and genotypic coefficient of variability (GCV) were highest for seed weight per plant and the lowest for maturity traits. Broad heritability for the 11 characters was moderate to high ranging from 0.40 - 0.86. The highest genetic gain (48.53%) was recorded on seed weight per plant and lowest on the maturity related traits. Pods number (r = +0.87) and raceme number (r = +0.81) had the highest positive and significant (P> 0.05) correlation with seed yield per plant. Path analysis revealed that pods per plant (0.68), racemes per plant (0.25) and pods per raceme (0.13) had the largest direct effect on seed yield. The study identified, moderate to high heritability and genetic advance estimates and significant positive correlations of pods per plant, raceme per plant, plant height, pod width, pods per raceme and number of flower nodes. The same traits also had high direct and indirect effects on seed yield and therefore suitable for phenotypic selection of improved determinate lablab genotypes. The results of the study are discussed in light of crop improvement of this leguminous crop.Item Variety Characteristics and Production Guidelines of Traditional Food Crops(Kenya Agricultural and Livestock Research Organization - Katumani Research Centre, 2006-04) Karanja, D.R.; Githunguri, C.M.; Ragwa, L.M.; Mulwa, D.; Mwiti, S.; Kenya Agricultural and Livestock Research Organization - Katumani Research CentreEastern, parts of Rift Valley and North Eastern are the main provinces constantly threatened by famine. Onyango et.al. (2006) have estimated that at any given time of the year 300,000 to 2,000,000 residents in these two provinces are receiving famine relief food. Unfortunately, Eastern and North Eastern provinces are major consumers of maize, which is not drought tolerant perse and hence does not perform well in these regions. About 80% of famine alarms are frequently raised in the arid and semi-arid lands (ASALs) of Kenya. Unfortunately, these famines are ignored and frequent need for food relief occurs despite the fact that the these regions can support the growth of drought tolerant traditional food crops such as sorghum, millet, beans, cowpeas pigeon peas, mungbeans, cassava and sweetpotatoes. In addition, most traditional food crops, especially sorghum, millets, cassava and sweetpotatoes are perceived as poor people’s food. This has frustrated the national efforts to promote these crops as viable, commercially marketable foods. Hence, it is not a wonder that products from these crops are hardly stocked in major supermarkets. There should be deliberate and concerted efforts by all stakeholders involved in food production to promote the production of traditional food crops in the ASALs and their utilization nationally if the humiliating famine and relief are to become a thing of the past.
