Genetic clustering, and diversity of African panel of released common bean genotypes and breeding lines

Common bean is a grain legume of global importance especially for proteins and micronutrients. The crop is a staple food in sub-Saharan Africa, where it has gained importance in iron biofortification for people prone to anemia. However, biotic and abiotic constraints, long cooking time, and high phytic acid and polyphenols both of which affect bioavailable iron, hinder the production and health benefits. To inform breeding decisions, the study determined genetic diversity and population structure within 725 breeding lines, varieties, or landraces mostly from Uganda and South America. Genotyping by sequencing and diversity array technology (DarTseq) were used to generate single nucleotide polymorphic markers on Set1 (427) and Set2 (298) germplasm, respectively. The germplasm were grouped into Andean and Mesoamerican gene pools, with the latter as the larger subpopulation. Analysis of molecular variance revealed 46% (Set1) and 50% (Set2) of genetic variation among the subpopulations, with fixation indices (F ST ) of 0.54 (Set1) and 0.71 (Set2) among Andean and Mesoamerican beans, respectively. The overall germplasm’s gene diversities were 0.206 (Set1) and 0.332 (Set2). Admixtures were the most diverse (0.193) in both sets of germplasm. The germplasm exhibited high genetic diversity and as a result they have a high potential for use in plant breeding. Inter-gene pool crosses within and across market classes are possible and considering both approaches is expected to increase diversity to realize genetic gain. The structure and polymorphic information generated provided useful perspectives for genomic breeding and genome-wide association study using the population.