Plasticidade fenotípica e análise de QTL para qualidade de sementes em soja

Abstract

Two surveys were conducted in this work with the intention to expand the knowledge of the soybean crop to grain yield and seed quality. In the first study the objective was to evaluate the adaptability and stability of soybean cultivars, considering the agronomic traits, grain yield and seed quality, adopting a univariate and multivariate approach. The experiments were conducted in a randomized block design in two crop years and three crop seasons. 17 commercial soybean cultivars were evaluated. For the evaluation of adaptability and stability, the Graphic Method and GGE biplot Method were employed. Previously, a selection index was conducted based on the sum of the standardized variables (Zij) obtained the selection index for the four traits evaluated together. In the Graphic Method, cultivars NA 7200 RR and CD 2737 RR showed the highest values of Z index. By the GGE biplot Method, were observed that cultivar NA 7200 RR presented greater stability in the univariate evaluation for grain yield as well as the selection Z index. In the second study aimed to identify QTL associated with traits related to physiological soybean seeds quality, such as vigor and germination. The experiments used to determine the genetic characteristics of seed vigor, including the percentage of seedling and percentage of germination seeds. The experiments evaluated RILs derived from the cross between Conrad and Sloan, generation lines F9:10 and F9:11, from 2012 and 2014, respectively. Significant differences of seed vigor were observed among the parents and RIL population from phenotypic analysis. A total of nine additive quantitative trait loci (QTL) for seed vigor were identified by Inclusive Composite Interval Mapping (ICIM) using IciMapping V4 software. Many QTL govern other important agronomic traits, the knowledge of these contributes to the development of high-yielding cultivars associated with high quality, disease and pathogens resistance.