Genetic control of common bean reaction to angular leaf spot

Abstract

The Carioca MG (susceptible = P 1 ) and Perola (resistant = P 2 ) cultivars were used as parents in a cross aiming at investigating the genetic control of the common bean plant reaction to Phaeoisariopsis griseola. Two hundred and fifty-one families (141 F 2:3 , 53 F 2 RC 11 and 57 RC 12 ) from this cross were evaluated for angular leaf spot severity in the leaves and pods, in two generations, under natural incidence of the pathogen. The genetic variance components, heritability in the broad ( 2 h ) and narrow ( 2 h ) senses and number of genes that control the reaction to angular leaf spot were estimated. The families were genetically different for level of resistance to the pathogen, and varied from 59.20% to 72.41% and varied from 19.32% to 73.79% for the leaf analysis. For reaction to the pathogen in the pods, the varied from 55.00% to 68.22% and was nil, indicating the presence of dominant alleles in the control of the trait, and of genes different from those responsible for the control of the disease in the leaves. Only one gene was estimated for the genetic control of the reaction to the pathogen in the leaves and two genes in the pods.