Genetic parameters and selection indexes in F2 and F2:3 soybean populations

The evaluation of genetic parameters in early generations select individuals in F-2 and F-2:3 and advancing only progenies with the potential to generate pure productive lines. The objectives of this study were to estimate genetic and phenotypic parameters in F-2 and F-2:3 populations derived from UFUS 7415 and TMG 7161 RR, evaluate different genotype selection strategies, and select progenies to improve agronomic traits. Populations in the F-2 and F-2:3 generations derived from a biparental cross between the parents UFUS 7415 and TMG 7161 RR were evaluated. The genetic parameters of 360 individuals in the F-2 generation and 150 genotypes of each parent were evaluated. Heritability varied from 4.66% for the number of seeds per pod to 86.06% for plant height at flowering. The greatest selection gain was obtained for plant height at flowering (29.68%), related to grain production. In the F-2:3 generation, 145 genotypes were evaluated and their parents, in a randomized block design with two replications. The correlations between characters and the genetic gains obtained by direct and indirect selection and based on the genotype-ideotype distance index and the Mulamba and Mock index of the sum of "ranks" were evaluated. With direct selection, selection gains ranged from -5.34 to 16.19%. The genotype-ideotype distance index showed a total selection gain of 40.49%, while the Mulamba and Mock index of the sum of ranks obtained a total gain of 39.35%. Twenty-three genotypes were selected for the characters evaluated with both indexes in the F-3 generation.