Diversidade genética e seleção de genótipos de soja

Abstract

During the development of new soybean genotypes, different stages are performed with different perspectives, such as selection of parents for artificial hybridization and evaluation and selection of superior progenies in advanced generations. This dissertation is subdivided into 3 chapters, with chapter 1 addressing the economic, botanical, genetic diversity and breeding aspects of soybean. The second chapter aimed to evaluate the genetic divergence between soybean genotypes, using dissimilarity measures so that these genotypes are used within the UFU Genetic Improvement Program as potential genitors. The research was conducted under field conditions in the experimental area of the Soybean Genetic Improvement Program. Were evaluated 25 progenies, which are constituted by segregating populations F4:5, RCF3:4, RCF4:5. Through univariate analysis, it can be concluded that the descriptors: epicotyl (EPI), petiole length of the first trifoliate leaf (PECTRI), rachis length of the first trifoliate leaf (RAQ), plant height at flowering (APF) and number days of flowering (NDF) are useful for the characterization and differentiation of soybean cultivars, and formation of superior genotype groups from the Tocher and UPGMA clusters. The third chapter aimed to estimate genetic parameters in soybean RCF4:5 and to select superior progenies for agronomic traits. Sixty-eight genotypes and 16 agronomic characters were evaluated. The selection indices provided the highest genetic gains for the two indices analyzed, they were related to traits linked to production (PROD), total number of pods (TNP) and grain weight per plant (GWP).