Abstract

Common beans are an important nutritious food crop to many people in developing countries. Inadequate soil-P is one of the major constraints to high bean seed yield productivity. Information about genetic effects that control inheritance of root traits in common bean grown under low soil-P conditions is scarce, and that is a challenge for genetic enhancement. This study was therefore implemented to determine inheritance and gene action of root traits in common bean for tolerance to low soil-P. The six generations were evaluated in a completely randomised design with two replicates under low soil-P in a pot experiment. Generation mean analysis revealed that both allelic and non-allelic genetic interactions controlled inheritance of root traits studied. Cumulative main gene effect was higher than epistasis effects. Additive genetic effects were more predominant than dominance effects. Additive and additive × dominance epistatic gene effects were more important in controlling inheritance of root traits under low soil-P. Broad-sense heritability for hypocotyl root number was the highest (93.98 %) while the narrow-sense heritability was moderate (51.13 %). To develop improved genotypes tolerant to low soil-P, recombination crossing should be followed by screening and selection in later generations for high seed yield, root and other preferred traits.

Key words: Common bean, inheritance, genotype, gene effect, heritability, low soil-P.