Selection of carioca common bean lines with slow darkening

The objective of this work was to evaluate the interaction between genotypes and environment for seed-coat darkening of common bean (Phaseolus vulgaris) seeds, in order to select lines that combine slow darkening, upright plants, resistance to lodging, and higher yield and 100-grain weight, with good adaptability and stability for these traits. Forty-four pre-selected lines, originating from crosses between one cultivar with slow darkening and prostrate plants and four cultivars with normal darkening and upright plants, were evaluated in field trials conducted in 15 environments (combinations of locations, crop seasons, and years). Considering the mean values, adaptability, and stability for each isolated trait, most of the lines presented satisfactory performance: 75% for slow darkening, 48% for high yield, 59% for upright plants, 84% for resistance to lodging, and 68% for 100-grain weight. The effects of environments and of the genotype by environment interaction are important for the five studied traits. The CNFC 16754 and CNFC 16820 lines present slow seed-coat darkening, high yield and 100-grain weight, more upright plant architecture, and greater resistance to lodging, besides high adaptability and stability for these traits, which shows their potential for recommendation as new cultivars and confirms that it is possible to join desirable phenotypes for the five traits evaluated.