ABSTRACT The iron concentration (FeC) and zinc concentration (ZnC) in common bean grain are quantitative traits, and appropriate breeding techniques are required to achieve genetic gain. The aim of this study was to obtain a recurrent selection population of black bean to increase the FeC and ZnC in the grain and to select the superior progenies for formation of the next cycle and obtain lines. The base population was formed by crosses among ten parents. A total of 351 progenies were obtained, and, after two generations of selection, the 27 best progenies were evaluated in two field trials for FeC, ZnC, 100 seed weight and yield. Analyses of variance were carried out and genetic parameters were estimated. The heritability estimates ranged from 59 to 94% for the four traits. The estimates of expected gain from direct selection for each trait (3 to 21%) and simultaneous selection (1 to 4%) indicate success from selection. The eight progenies, selected based on simultaneous selection, have superior mean values, including to those of ‘BRS Supremo’ (10% for FeC, 8% for ZnC, 5% for 100 seed weight and 3.8% for yield), the Brazilian black bean cultivar with the highest FeC and ZnC. The recurrent selection population shows high genetic variability and potential for obtaining lines superior to the cultivars currently on the market, allying high agronomic performance and high FeC and ZnC in the grain. Furthermore, this population shows potential for generating a new recurrent selection cycle, from recombination of the eight superior progenies.

Resumo O objetivo deste trabalho foi avaliar a interação entre genótipos e ambientes para o escurecimento de grãos de feijão carioca (Phaseolus vulgaris), a fim de selecionar linhagens que associem escurecimento lento, arquitetura ereta, tolerância ao acamamento, e maior produtividade e peso de 100 grãos, com boa adaptabilidade e estabilidade para esses caracteres. Foram avaliadas 44 linhagens pré-selecionadas, oriundas de cruzamentos entre uma cultivar com escurecimento lento e arquitetura prostrada e quatro cultivares com escurecimento normal e arquitetura ereta, em experimentos de campo conduzidos em 15 ambientes (combinações de locais, épocas de semeadura e anos). Ao se considerar as médias, a adaptabilidade e a estabilidade para cada caráter isoladamente, a maior parte das linhagens apresentou desempenho satisfatório: 75% para escurecimento lento, 48% para alta produtividade, 59% para arquitetura ereta, 84% para tolerância ao acamamento e 68% para peso de 100 grãos. Os efeitos dos ambientes e da interação entre genótipos e ambientes são importantes para os cinco caracteres estudados. As linhagens CNFC 16754 e CNFC 16820 apresentam escurecimento lento dos grãos, alta produtividade e peso de 100 grãos, plantas mais eretas e alta tolerância ao acamamento, além de alta adaptabilidade e estabilidade para esses caracteres, o que mostra o seu potencial para recomendação como novas cultivares e confirma que é possível reunir fenótipos desejáveis para os cinco caracteres avaliados.

Abstract 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.