Diversidade genética em linhagens avançadas de soja oriundas de cruzamentos biparentais, quádruplos e óctuplos

Abstract

The aim of this study was to analyse the genetic diversity and agronomic performance of a group of advanced and superior strains of soybean, derived from biparental, four-way and eight-way crosses, in order to identify future promising and superior combinations. The experiment was carried out in the experimental area of the Paulista State University, Júlio de Mesquita Filho, Jaboticabal Campus, in the state of São Paulo, Brazil. The characteristics under evaluation were: number of days to flowering, plant height at flowering, number of days to maturity, plant height at maturity, height of the first pod, number of branches, number of pods per plant, agronomic value, lodging, one hundred seed weight and seed yield., The Mahalanobis distance and the relative contribution of each characteristic were used to calculate the phenotypic distances. Among the genotypes analysed, 19 strains displayed high productivity, being superior to the controls (V-max, CD 216, CD 219 and Conquista). The greatest distance found was between strains JAB 41 and JAB 17 (279.81), followed by JAB 40 and JAB 17 (261.38) and between JAB 40 and JAB 22 (255.46). There were six groups formed using the Ward method, indicating the presence of genetic variability among the tested strains. Increasing the number of parents had no effect on the increase in genetic diversity between the strains, and was not the factor responsible for the grouping or not of the genotypes under test.