Selection of parents and segregating populations of common bean with high agronomic potential and slow seed-coat darkening

ABSTRACT Choosing parents and segregating populations are fundamental steps for the success in plant breeding. For the common bean crop, the development of genotypes that combine favorable agronomic traits and seed quality may increase the chances of adopting new cultivars. This study aimed to select promising parents and segregating populations to develop slow seed-coat darkening lines, together with high grain yield, lodging tolerance and short seed cooking time after storage, as well as to investigate the relationship between seed-coat darkening and seed cooking time after storage. Twenty segregating populations (F3, F4 and F5 generations) and their parents were evaluated. The sum of ranks index for combined traits was used in the selection of superior populations. Genetic and phenotypic correlations between seed-coat darkening and cooking time after storage were estimated. Among the parents, the BRSMG Madrepérola cultivar was the most promising to generate lines with seed-coat darkening. The superior populations were BRSMG Madrepérola x IPR Saracura, BRSMG Madrepérola x BRS Sublime, BRSMG Madrepérola x BRS Estilo and BRSMG Madrepérola x BRS Notável. A linear relationship was not found between seed-coat darkening and seed cooking time after storage, indicating that the first trait is not an adequate indicator to infer about seed cooking time.摘要 亲本选择与分离群体构建是植物育种成功的核心基础步骤。对于普通菜豆作物而言，培育兼具优良农艺性状与种子品质的基因型，可提升新品种推广应用的可行性。本研究旨在筛选潜力亲本与分离群体，以培育兼具种皮缓慢褐变、高籽粒产量、抗倒伏性及贮藏后缩短籽粒蒸煮时间的品系，同时探究种皮褐变与贮藏后籽粒蒸煮时间间的关联。本试验共评估了20个分离群体（F3、F4及F5代）及其亲本，采用综合性状秩和指数开展优良群体的筛选工作，并估算了种皮褐变与贮藏后籽粒蒸煮时间间的遗传相关与表型相关。结果显示，亲本BRSMG Madrepérola是培育种皮缓慢褐变品系的最具潜力亲本；筛选得到的优良分离群体包括BRSMG Madrepérola × IPR Saracura、BRSMG Madrepérola × BRS Sublime、BRSMG Madrepérola × BRS Estilo以及BRSMG Madrepérola × BRS Notável。未发现种皮褐变与贮藏后籽粒蒸煮时间间存在线性相关，表明种皮褐变性状不足以作为推断籽粒蒸煮时间的有效指标。