Clustering common bean mutants based on heterotic groupings

Abstract

Common bean (Phaseolus vulgaris L.), is an important legume crop in sub-Saharan Africa (SSA). Most of the local varieties are favoured for their colour and taste, but have a low yield potential of 0.3 to 0.5 metric tonnes per hectare. Mutation breeding is a crop improvement tool in beans that can create new alleles, which when advanced beyond mutated generation 5 (M5), produces stable mutants, which may possess desirable  characteristics. These mutants may result in rapid genetic advance and help address issues of low bean productivity. The objective of this study was to cluster bean mutants from a bean mutation breeding programme, based on heterotic groupings. This was achieved by genotyping 16 bean genotypes, using 21 Simple Sequence Repeats (SSR) bean markers. From the results, three different clusters A, B and C, were obtained suggesting great genetic diversity among the bean mutants and these cluster groups (A, B and C) can be taken as heterotic groupings. Depending on the phenotypic trait under consideration, crossing of two distinct genotypes from different cluster groups may lead to hybrid vigour. Furthermore, to create genetic variability for further bean improvement, the breeder can cross distinct genotypes from different cluster groups, which after several generations of selfing accompanied by selection may lead to desirable progenies

Key Words: Genetic variation, mutation breeding, Phaseolus vulgaris