Estratégias de seleção em populações segregantes de soja para baixas latitudes no cerrado

Abstract

The parent selection for crossings is one of the most important steps in breeding programs where the prediction of the genetic potential of hybrids allows the breeder to channel human and financial resources at higher populations. In this sense, the objective of this study was to estimate the general (GCA) and specific combining ability (SCA) of seven soybean genotypes, in two generations (F1 and F2), according to Griffing (1956) without the reciprocals, in order to indicate parents and hybrid combinations that are promising to achieve new favorable combinations. The F1 hybrids, F2 populations and the parents were evaluated in Gurupi-TO, being the generation F1 evaluated in greenhouse and the F2 generation in the field. The measured parameters were number of days to flowering and of number days to maturity, number of seeds per pod, number of pods per plant, weight of hundred seeds and grain yield per plant. For all attributes was detected significant effect for SCA. The results of the diallel analysis were concordant in the F1 and F2 generations. The M-8360 and A-7002 parents gather alleles favorable to reducing the number of days to flowering and number of days to maturity in soybean. Hybridization M-8360 x BRS Valiosa is promising to obtain early cycle soybean strains. The M-8360 parent is promising for population improvement programs. Hybridization M-8867 x M-8360 is promising for formation of superior segregants.