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.

Selection strategies for identifying fast cooking, mineral-biofortified bean cultivars with high agronomic performance

“…Therefore, for none of the economic weights associated with the ranksum index was it possible to obtain favorable genetic gains in the selection of all evaluated traits, confirming previous results described for the selection of superior common bean cultivars (Ribeiro et al, 2019a, b;Ribeiro and Mezzomo, 2020). The rank-sum index was also used for ranking the common bean genotypes regarding the traits analyzed (Dias et al, 2020;Silva et al, 2018;Zanottti et al, 2020). The genotypes classified in the first positions were not superior for all the determined traits, which constituted a limitation in the use of the rank-sum index for simultaneous selection in commonbean breeding programs.…”

“…This is because direct selection allowed for a high genetic gain for traits analyzed individually, but caused undesirable changes in other important traits for selection (Jost et al, 2012;Maziero et al, 2015). Selection indices, in turn, allowed for the identification of superior common bean cultivars for several traits (Arns et al, 2018;Bertoldo et al, 2010;Dias et al, 2020;Gomes et al, 2018;Jost et al, 2012;Maziero et al, 2015;Ribeiro et al, 2019a;Silva et al, 2018;Zanotti et al, 2020), thereby enhancing the efficiency of breeding programs.…”

Genome-wide association mapping reveals new loci associated with light-colored seed coat at harvest and slow darkening in carioca beans

“…In the case of the carioca variety, among the 138 genotypes evaluated, all cultivars lost L* values greater than two points after 30 days, showing the absence of the ND phenotypic class for the variety. In addition, the cultivar considered as the standard for SD in previous studies [ 10 , 23 , 33 , 41 ] was the second most tolerant genotype to PHD (-2.46 L*).…”

Factors affecting the cooking quality of stored carioca beans (Phaseolus vulgaris)

“…Genetic variation occurs in seed coat darkening of many bean classes including carioca beans (Rodrigues et al, 2019). The variation can be monogenic or oligogenic, which means their inheritance is controlled by one or a few genes (Silva et al, 2018). In carioca beans, the darkening phenotype is controlled by a single recessive gene "Sd, " the slow darkening is represented by the "sd" recessive allele (Silva et al, 2008).…”

“…Proanthocyanidins are oligomeric flavonoids composed mainly of catechin and epicatechin with the slow darkening trait are relatively simple, given its high heritability and simple genetics, the genetic complexity of many interesting characteristics makes this selection difficult in breeding programs. However, the slow darkening trait is expressed maternally and inherited recessively (Silva et al, 2018;Alvares et al, 2019).…”