SELECTION OF LINEAGES, GENETIC PARAMETERS, AND CORRELATIONS BETWEEN SOYBEAN CHARACTERS

Soybean has great economic importance in the world accordingly, this legume has been exploited in breeding programs aiming to provide cultivars with extensive grain yield, tolerant to pests and diseases, and adapted to different soil and climatic conditions. Therefore, the objectives of this study were to evaluate genetic parameters and correlations between soybean traits to select lineages to increase yield and improve agronomic traits. Experiments were carried out on the Capim Branco farm, of the Federal University of Uberlandia, harvest in 2016/2017. Fifteen morph-agronomic traits were assessed on twenty-two genotypes in a randomized complete block design with three replicates. Agronomic traits related to cycle, height, number of nodes and total pods have shown coefficients of genotypic determination higher than 70%. In addition, coefficients of variation of the number of days to the flowering and number of days to maturity were equal to 3.79% and 4.87%, respectively, indicating high homogeneity of data and low random variation. Among evaluated traits, ten have presented the ratios between the coefficient of genetic variation (CVg) and coefficient of environmental variation (CVe) above one, demonstrating high success likelihood in the selection of these traits. Fifteen genotypes have presented grain yield above the national average of the 2016/2017 harvest, which was 2882 kg h(-1). Significant phenotypic correlations between traits ranged from -0.49 to 0.89, however genotype correlation was higher than the phenotypic ones, indicating that genetic factors have contributed more than the environmental factors. Traits related to cycle, height, and the number of nodes in the main stem have presented measures of H-2 and CVg / CVe with extensive magnitudes, evidencing the possibility of selection lineages having superior traits in the Soybean Breeding Program of the Federal University of Uberlandia. To increasing grain yield, the traits Number of pods of three grains and the Total number of pods were identified as appropriated to indirect selection based on the phenotypic and genotypic correlations. The 21P14, B2P1, B2P28, B1P33 and 2AP11 lineages stand out as superior genotypes to direct selection.