Combining ability of soybean in F1 and F2 generations for earliness and grain yield

Parental selection is a key step in genetic improvement programs, as it impacts the genetic potential of the segregating population and the genetic progress that can be achieved. This selection can be made through predictive or diallel analyses, which estimate general (GCA) and specific combining abilities (SCA). This study evaluated F-1 and F-2 soybean (Glycine max) populations derived from diallel crosses to select parents for traits related to earliness, production components, and grain yield. Fifteen treatments were analyzed in a randomized complete block design, including 10 biparental combinations and 5 parent lines (TMG 801, TMG 803, BRS 511, UFUS 7101, and UFUS 7201). Traits assessed were days to flowering and maturity, plant height at maturity, height of first-pod insertion, number of nodes at maturity, branched nodes, productive nodes, pods with one, two, and three grains, total pods per plant, seeds per pod, and grain yield. Results indicated that evaluating the F1 generation was sufficient, as parent characteristics were consistent in the F2 generation. The diallel analysis identified promising combinations for reducing the growth cycle and increasing productivity and grain yield. BRS 511 x TMG 803, UFUS 7201 x TMG 803, and TMG 803 x UFUS 7101 showed the greatest potential.