INHERITANCE - LOW CORRELATIONS OF LEAF, POD, AND SEED REACTIONS TO COMMON BLIGHT DISEASE IN COMMON BEANS - AND IMPLICATIONS FOR SELECTION

The heritability of leaf, pod, and seed reactions; stem color and abaxial leaf pubescence; and the association of these traits were studied in advanced dry bean recombinant inbred lines derived from the Phaseolus vulgaris crosses 'PC-50' x XAN-159, 'PC-50' x BAC-6, and 'Venezuela 44' x BAC-6. The reaction to Xcp was quantitatively inherited in all three plant organs. Qualitative inheritance was found for stem.color and leaf pubescence. Low to intermediate heritability values were obtained for the leaf and seed reactions to Xcp. Heritability estimates were consistently low for the pod reaction to Xcp. Low nonsignificant Pearson correlations were detected between leaf and pod reactions, leaf and seed reactions, and pod and seed reactions, except for the latter two correlations, which were low and significant in lines from the cross 'PC-50' x XAN-154. Genetic correlations between leaf and pod reactions and leaf and seed reactions were low and significant in lines from all crosses, except for Venezuela 44 x BAC-6 in the latter case. Genetic correlations between pod and seed reactions were low and nonsignificant, except in the cross 'PC-50' x XAN-159, for which a low significant correlation was observed. No significant association was found between Xcp leaf reaction and stem color or leaf pubescence. A breeding strategy for improving resistance to Xcp in P. vulgaris is discussed.