Genome-wide association mapping and genomic prediction for CBSD resistance in Manihot esculenta
Cassava (Manihot esculenta Crantz) is an important security crop that faces severe yield loses due to cassava brown streak disease (CBSD). Motivated by the slow progress of conventional breeding, genetic improvement of cassava is undergoing rapid change due to the implementation of quantitative trait loci mapping, Genome-wide association mapping (GWAS), and genomic selection (GS). In this study, two breeding panels were genotyped for SNP markers using genotyping by sequencing and phenotyped for foliar and CBSD root symptoms at five locations in Uganda. The results provide an insight into the genetics of CBSD resistance to guide CBSD marker-assisted breeding and highlight the potential of GS to improve cassava breeding.
The Interactive Effect of Residue Quality, Quantity, Soil Texture and N Management on Maize Crop Yield in Ghana
Food insecurity and declining soil fertility across much of sub-Saharan Africa in recent decades have led to pursuit of alternative nutrient management strategies for both improving crop yields and the restoration of degraded soils. This 3-year field-based study involving two sites of contrasting soils in the semi-deciduous forest zone of Ghana offers recommendations for improving the profitability, sustainability and efficiency of nutrients through site specific fertilizer in West Africa Agro-Ecosystems.
Identification of Quantitative Trait Loci for Grain Yield and Other Traits in Tropical Maize Under High and Low Soil-Nitrogen Environments
Low soil Nitrogen (low-N) is one of the most important abiotic stressors responsible for
significant yield losses in maize (Zea mays L.). The development and commercialization of low-N–tolerant genotypes can contribute to improved food security in developing countries. Marker-assisted breeding holds great promise for improving such complex traits more efficiently and in less time, but requires markers associated with the trait of interest. This study identified 13 QTL with 158 SNP markers, of which nine and four QTL were detected under low- and high-N environments, respectively. These QTL would be invaluable for rapid introgression of genomic regions into maize populations using marker-assisted selection (MAS) approaches.