Simultaneous selection for seed physiological quality traits in common bean cultivars under drought stress

ABSTRACT Selection for high seed germination and vigor under drought stress has received little attention in common bean breeding programs. In this context, the objectives of this study were to evaluate the phenotypic variability of common bean cultivars for seed physiological quality under drought stress, analyze the correlation among these traits, and select cultivars with high germination and vigor under such conditions. To this end, seeds of 25 common bean cultivars were produced over two growing seasons under drought stress. Seed physiological quality was assessed through the germination, first count, germination speed index, mass electrical conductivity, accelerated aging, and cold tests. Significant cultivar and cultivar × environment interaction effects were observed for all tests in the combined analysis of variance. The tests used allowed for differentiation among cultivars; however, they did not show complete agreement in identifying those with the highest seed physiological quality. Germination was not correlated with the germination speed index, mass electrical conductivity, accelerated aging, or cold tests. Therefore, the combined use of these five tests provides greater efficiency in selecting cultivars with high seed physiological quality under drought stress. The presence of phenotypic variability for seed germination and vigor favors simultaneous selection using the multiplicative index. Cultivars SCS 205 Riqueza, IPR Juriti, BRS Esplendor, IPR Tangará, and Fepagro 26 demonstrate high seed physiological quality under drought stress.