Heterosis and combining ability for grain and biomass yield in sorghum hybrids for the semi-arid lowlands of Eastern Kenya

Sorghum [Sorghum bicolor (L.) Moench] is an important cereal crop used for food, feed, and industrial raw material. In Kenya, it’s a food and nutritional security crop in the semi-arid areas which are prone to maize crop failures. The study aimed at estimating the combining ability and heterosis for grain and biomass yield among sorghum hybrids. Thirty- four F1 sorghum hybrids, their parents and a check were evaluated at two KALRO research centers in Kenya during the 2014-2015 cropping seasons. Square lattice trial design with three replications was used and fourteen agro-morphological traits studied at each location. The combined analysis of variance showed highly significant differences (p<0.001) for genotypes and locations for all traits, except for leaf length. Fresh biomass yield, panicle exertion, and plant height had high heritability, genotypic coefficient of variation (GCV) and genetic advance (GA %) showing the predominance of additive gene effect in their inheritance, hence these traits can be improved through direct phenotypic selection. Hybrid parents ICSR 89058, ICSV 700 and ICSR 160 were good general combiners for earliness, biomass and grain yield respectively. The highest grain and biomass yielders were ATX 623 x Macia and ICSA 206 x IESV 91104DL respectively. High magnitudes of SCA effect coupled with high heterobeltiosis, mean and standard heterosis for grain and biomass yield were noted in hybrids ATX 623 x Macia and ICSA 11035 x Macia respectively. These hybrids can be promoted for on-farm testing and possible release for food and fodder. Therefore, the improvement of sorghum grain and forage yields in the semi-arid areas of Kenya can be done simultaneously through the exploitation of heterosis by developing hybrids

Morphological Characterization and Selection of Spider Plant (Cleome Gynandra) Accessions from Kenya and South Africa

Characterization of selected spider plant accessions from Kenya and South Africa was performed in order to individuate those with distinct morphological traits for future improvement programs. For this purpose, thirty two accessions of spider plant, 23 sourced from Kenyan genebank and nine sourced from South African genebank, were planted at the University of Nairobi’s Kabete field station, in a randomized complete block design with 3 replications. Eleven morphological traits based on modified FAO (1995) spider plant descriptors were used in characterization. Traits evaluated were growth habit, flower colour, stem colour, stem hairiness, petiole colour, petiole hairiness, leaf colour, leaf pubescence, leaf shape, leaf blade tip shape, and number of leaflets per leaf. The scored data were analyzed using DARwin software v6 and Genstat v14. Shannon diversity index (H’), multivariate methods of principal component analysis and hierarchical clustering analyses of unweighted pair group method of arithmetic mean were assessed for all the traits. Estimates of Shannon-Weaver diversity index (H’) for the morphological traits were generally high (H’>0.500). The H' index indicated inter-country diversity to be greater than the intra-country diversity. Principal component analysis identified seven important morphological traits (stem colour, stem hairiness, petiole colour, petiole hairiness, leaf hairiness, leaf shape and number of leaflets per leaf) for characterizing spider plant accessions. The hierarchical cluster analysis revealed two major clusters (Cluster I and II) for the 32 accessions grown, with clustering of accessions occurring along regional basis. Cluster I consisted of South African accessions only while cluster II had mainly Kenyan accessions and two South African accessions. The relatively high levels of dissimilarity revealed in this study among the accessions for traits evaluated, especially accessions from the two different countries, indicates high prospects for genetic improvement of the crop through cross breeding by using materials from different geographical origins

Sorghum production practices in an integrated crop-livestock production system in Makueni county, eastern Kenya

Productivity of sorghum has been below potential in arid and semi-arid lands of Kenya, due to poor agronomic practices and soil nutrient deficiency. Sorghum crop is fairly drought tolerant, resistant to waterlogging, and yields are reasonably better in infertile soils compared to other crops. Proper agronomic practices would significantly increase yields as well as nutrient content in grains and crop residues used as livestock feed. The objective of this study was to investigate the existing sorghum production practices and sorghum use as food and feed sources. A survey involving 90 farmers from sorghum producing areas in Makueni County was conducted. The survey focused on the varieties and fertilizers used, trends in yields, constraints to sorghum production and the present strategies used for sorghum as animal feed. Most farmers (84.4%) used uncertified seeds from own saved sources, and the commonly grown variety was Seredo (44.5%) due to resistance to bird damage. The majority (32.1%) of farmers recorded very low yield of sorghum grain, from151 to 250 kg ha-1. Most farmers (68.9%) used farmyard manure in sorghum production, while 30.9% of the farmers did not use any fertilizer. All farmers indicated that their greatest challenge in sorghum production was inadequate rainfall. Bird damage to the crop was a chronic problem to most (73.3%) farmers. The majority (58.9%) of farmers conserved sorghum residue for feed as hay. The findings show the need to provide technical information and guidance on the production practices, such as choosing best-yielding seed varieties, proper methods of pest and disease control and proper use and conservation of sorghum residue as animal feed

Post-harvest evaluation of selected hybrids to maize weevil Sitophilus zeamais resistance

Sitophilus zeamais has been identified as one of the most destructive pests of maize stored in tropical regions. While most maize hybrids are being developed, it is necessary to evaluate their resistance to this pest. This study determined the resistance of selected maize hybrids to infestation by S. zeamais. Twenty two hybrids with varying resistance to weevil infestation and two checks DUMA 41-suceptible and MTP0701-resistant were used in a randomized complete block design experiment. Assessment was done at 10, 60 and 120 days of maize storage. Data was collected on percent weevil damage, grain weight loss and number of live and dead weevils. Heritability and correlation of factors were also estimated. Analysis of variance showed significant differences (P ≤ 0.05) on weight loss. The selection of the resistant genotypes was based on percent weight loss after 60 days. KH631Q and PH4 were selected as the most resistant and moderately resistant hybrids, respectively. The resistant check MTPO701 was also found to maintain resistance to weevil attack. There was a strong positive correlation between weight loss, number of live weevils and percent damage. Moderate heritability estimates of hybrids at 60 days of storage indicated the possibility of their parents to transfer the desirable traits to subsequent generations. Therefore, parents of the resistant hybrids could be utilized in breeding programs for maize weevil resistance and be deployed to farmers for use, respectively

Preservation of Postharvest Quality of Leafy Amaranth (Amaranthus spp.) Vegetables Using Evaporative Cooling

Leafy vegetables are very highly perishable and must be utilized immediately after harvest. Their fast deterioration is attributed to various biological and environmental factors with temperature playing a central role. Evaporative cooling is a low-cost temporary storage technology that offers smallholder vegetable farmers an alternative to expensive cold rooms. The present study sought to determine the effectiveness of evaporative cooling using zero energy brick cooler (ZEBC) and evaporative charcoal cooler (ECC), to preserve the postharvest quality of leafy amaranth vegetables. Freshly harvested vegetables were separated into bundles weighing 300 grams and stored under ZEBC, ECC, and ambient room conditions (control). Real time changes in temperature and relative humidity (RH) as well as changes in quality attributes (physiological weight loss (PWL), wilting index, hue angle, and vitamin C) were determined during the storage period. The temperature difference between the ZEBC and ECC versus the ambient air ranged between 4 and 10°C. Significantly higher RH (80–100%) was recorded in both evaporative cooling chambers. At the end of storage, higher PWL (47.6%) was recorded at ambient room conditions compared to 10.5 and 6.7% under ZEBC and ECC, respectively. A rapid decline in vitamin C (51%) was reported in vegetables stored at ambient room conditions. Overall, there was better vegetable quality preservation under ECC and ZEBC

Participatory Selection of Cowpea Varieties in Kilifi County of Kenya

Aim:&nbsp;To identify farmer preferred cowpea varieties in coastal lowland Kenya. Study Design:&nbsp;The experiment was laid out in a randomized complete blocks design with three replications. Place and Study Duration:&nbsp;Tezo location, Bahari division, Kilifi County, Kenya during July – October 2011/2012 cropping seasons. Methodology:&nbsp;Thirty nine farmers (30 female and 9 male) from three farmer groups in Tezo location, Kilifi County participated in the establishment and evaluation of 11 cowpea varieties using their own selection criteria. The varieties were evaluated at flowering, podding, maturity and post harvest stages. Farmers’ cowpea selection criteria before flowering and at podding were high grain yield, drought tolerance, early maturity, ease of harvesting and leafiness. Results:&nbsp;Kutambaa, KVU 27-1 and Nyeupe were rated top varieties at these stages. Farmers’ selection criteria at maturity and after harvest included grain yield, color, taste and cooking duration. KVU 419, Kaima koko and Nyeupe were rated top varieties at these stages. Grain yield varied from 3.3 t ha-1&nbsp;(KVU 419) to 0.48 t ha-1&nbsp;(Kaima koko). Conclusion:&nbsp;The results of this study have demonstrated the need for plant breeders to integrate grain color, taste and cooking duration traits in cowpea improvement programmes. Integration of KVU 419, Nyeupe, KVU 27-1 and Kutambaa cowpea varieties into the maize-based system is likely to improve cowpea productivity in Kilifi County, Kenya

Influence of P Fertiliser on Nodulation, Growth and Nutrient Content of Cowpea (Vigna unguiculata L.) in Acidic Soils of South Western Kenya

Field experiments were carried out in Kericho East (0°22' S, 35°17' E) and Bomet central (0°47' S, 35°21' E) to determine the effects of liming and phosphorous (P) fertiliser on nodulation, growth, yield and nutrient content of cowpea in the strongly and moderately acidic soils. The treatments comprised of three cowpea varieties (KVU 27-1, M66 and Ngor) supplied with lime&nbsp; (0 t CaO ha-1&nbsp;and 4 t CaO ha-1) and P fertiliser&nbsp; (0 kg P ha-1, 25 kg P ha-1&nbsp;and 50 kg P ha-1), laid out in a randomized complete block design in a 2 x 3 x 3 factorial arrangement. Data collected were: nodule number and weight, leaf area index, shoot dry weight, shoot and grain N and P uptake, grain yield, tissue N and protein content. Results showed that liming had no significant (P&nbsp;≤.05) effects on cowpea nodulation at experimental sites characterised by strongly acidic (pH 4.85) and moderately acidic (pH 5.58) soils, but increased shoot dry matter by 35% and grain N and P uptake in the strongly acidic soils of Kericho East by 1.8 kg ha-1&nbsp; and 2 kg ha-1&nbsp;respectively. In absence of liming or P fertiliser, grain yield was not recorded in two varieties at Kericho East. Application of 50 kg P ha-1significantly enhanced nodulation at both experimental sites; it increased nodule dry weight at Bomet Central by 27% in the short rains than in the long rains season. Lower P rate (25 kg ha-1) increased shoot dry matter by 46% at Bomet central, but 50 kg P ha-1&nbsp;increased growth parameters of cowpea by over 100% at Kericho East in all seasons. It is concluded that liming is not beneficial to cowpea nodulation in soils with similar ecological conditions reported in this study. Application of 50 kg P ha-1&nbsp;is required for cowpea production in strongly acidic soils