Genetic Diversity and Population Structure of Sorghum (Sorghum bicolor (L.) Moench) Landraces Using DArTseq-Derived Single-Nucleotide Polymorphism (SNP) Markers.

Genetic integrity of an accession should be preserved in the conservation of germplasm. Characterization of diverse germplasm based on a molecular basis enhances its conservation and use in breeding programs. The aim of this study was to assess the genetic diversity of 169 sorghum accessions using a total of 6977 SNP markers. The polymorphic information content of the markers was 0.31 which is considered to be moderately high. Structure analysis using ADMIXTURE program revealed a total of 10 subpopulations. Neighbor-joining tree revealed the presence of six main clusters among these subpopulations whereas in principal component analysis, seven clusters were identified. Cluster analysis grouped most populations depending on source of collection although other accessions originating from the same source were grouped under different clusters. Analysis of molecular variance (AMOVA) revealed 30% and 70% of the variation occurred within and among accessions, respectively. Gene flow within the populations was, however, limited indicating high differentiation within the subpopulation. Observed heterozygosity among accessions varied from 0.03 to 0.06 with a mean of 0.05 since sorghum is a self-pollinating crop. High genetic diversity among the subpopulations can be further explored for superior genes to develop new sorghum varieties.

Ridge-furrow with grass straw mulching farming system to boost rainfed wheat productivity and water use efficiency in semiarid Kenya.

BACKGROUND: Ridge-furrow mulching farming systems (RFMs) aim to increase field productivity and improve water use efficiency. To explore environment-friendly and efficient farming systems is a central aspect of rainfed wheat field management in Kenya where rainfall utilization is at a low level. We introduced RFMs (including plastic film and grass straw mulching) to semiarid Kenya to evaluate the effects on field productivity, rainwater utilization, soil quality and economic profitability using old and modern wheat cultivars from 2012 to 2013. RESULTS: Across the cultivars, the RFMs increased grain yield, aboveground biomass and water use efficiency by 74-163%, 36-104% and 89-273%, respectively, compared with conventional flat planting (control). RFMs significantly shortened the vegetative period while prolonging the reproductive period. The net economic output under RFMs was 74-165% higher than that of the control. Grass straw mulching achieved the highest economic output to input ratio, almost 45% higher than plastic film mulching, despite the former harvested only 82% of the maximum field productivity of the latter. Compared with the control, grass straw mulching promoted the contents of soil organic carbon, total nitrogen and C:N ratio by 14%, 8% and 5%, respectively, while obviously decreased values of these parameters were observed under plastic mulching. CONCLUSIONS: Through reducing soil water loss, and improving rainwater use efficiency and soil quality, ridge-furrow grass straw mulching would be a sustainable option for boosting field productivity and thus ensuring local food security in rainfed agricultural areas of Kenya. © 2020 Society of Chemical Industry.

Yield-phenology relations and water use efficiency of maize (Zea mays L.) in ridge-furrow mulching system in semiarid east African Plateau.

Yield-phenology relation is a critical issue affecting rainfed maize field productivity in semiarid east African Plateau (EAP). We first introduced Chinese ridge-furrow mulching (RFM) system to EAP, using three maize cultivars with early-, mid- and late-maturing traits as test materials. A two-year field experiment was conducted in a semiarid farm of Kenya from 2012 to 2013. Three treatments were designed: alternative ridge and furrow with transparent plastic mulching (FT), with black plastic mulching (FB) and without mulching (CK). We found that FT and FB significantly increased soil moisture and accelerated crop maturity across two growing seasons. Leaf area and shoot biomass were increased by 30.2% and 67.5% in FT, 35.2% and 73.5% in FB, respectively, compared with CK. Grain yield, water use efficiency and economic output were increased by 55.6%, 57.5% and 26.7% in FT, and 50.8%, 53.3% and 19.8% in FB, respectively. Optimal yield and economic benefit were observed in late-maturing cultivar due to increased topsoil temperature in FT in 2012 (cool), and in early-maturing cultivar owing to cooling effect in FB in 2013 (warm). Our study suggested RFM system, combined with crop phenology selection, be a promising strategy to boost maize productivity and profitability in semiarid EAP.

Consumption patterns and preference of milk and milk products among rural and urban consumers in semi-arid Kenya.

Milk consumption in the semi-arid regions of Kenya is not well understood. A study was carried out on consumption of milk and milk products in the semi-arid region of eastern Kenya. A total of 135 rural and 126 urban households were interviewed. Raw milk was the most popular and was consumed by 99% and 84% of rural and urban households, respectively. Generally as degree of processing increased, the frequency of consumption declined from more than once per day to 1-2 times a week and eventually to occasionally. Richer households consumed significantly (p < .05) more milk and milk products than poor households. Raw milk was preferred over pasteurized, ultra high temperature treated, and powdered milk because it was cheaper and widely available. In order to improve consumption of different milk products, there is need to improve availability particularly in the rural areas.