Parâmetros genéticos e seleção de progênies F2:3 e F2:4 em soja

Abstract

The soybean cultivation has world ide due its high protein and oil present in the grain, being considered an oleaginous plant with high nutritional values. The estimation of genetic parameters is of extreme importance to the knowledge of the breeder, because it allows you to know the nature genetic of characters in a population that is being studied allowing assist also in the best strategies for selection of superior genotypes. In the objective of this study aimed to estimate genetic parameters in F2: 3 and F2: 4 and and selecting superior genotypes in accordance with the selection strategies. Two experiments were conducted at the experimental farm Capim Branco, in the city of Uberlândia, Minas Gerais. The first experiment was sown in February 2018. Were evaluated 154 soybean genotypes in F3 generation developed by the soybean breeding programo f the UFU, a randomized complete block design with two replications. Were initially evaluated the genetic parameters and genetic gains obtained subsequently by direct and indirect selection and based on index from the traits e evaluated: Number of days to flowering (NDF), number of days to maturity (NDM); Plant height at flowering (APF); Plant height at maturity (APM); Height of insertion of the first pod (AIV): Total number of nodes (NNT); Number of nodes productive (NNP); Number of pods with 1 grain (NV1G); Number of pods with 2 grains (NV2G); Number of pods with 3 grains (NV3G). We found the existence of genetic variability among the genotypes studied for all agronomic traits studied. The heritability of traits related to the cycle, plant height at maturity, number of nodes at flowering, and productivity components were considered high in this experiment, demonstrating that the existing variance for these traits can be attributed to the greater part by genetic causes. The classic index proposed by Smith (1936) and Hazel (1943) showed higher total gain of selection when compared to direct selection and selection by index of Mulamba & Mock (1978). The second experiment was conducted in the 2018/2019 season, where they were evaluted 45 soybean genotypes in F4 generation and five witnesses. All characters evaluated showed high heritability values (> 70) and Cvg / Cve greater than a unit, showing favorable situation for direct selection for these traits. The direct selection presented higher selection gains for the character of productivity as well as the Mulamba & Mock (1978).