Genetic variability among soybean cultivars, under different edaphoclimatic conditions, in center south region of the state of Tocantins

Abstract

In order to evaluate the genetic divergence between twelve soybean cultivars, the essays were carried out at Formoso do Araguaia, TO, in the inter-cropping 2007. The soybean cultivars studied were DM Vitória, MG/BR 46 (Conquista), Suprema, BRS Pintado, DM 247, BRS MG 68, BRS MG Liderança, BRS MG Segurança, DM 339, BRS MG Garantia, A 7002 e DM 309. Genetic divergence was evaluated by multivariate procedures: generalized Mahalanobis distance, the grouping optimization method of Tocher, nearest neighbor and the technique of canonical variables. It was evaluated the following characteristics: grain production per plant, number of seeds per pod, number of pods per plant, number of days for blooming; number of days for maturation, plant height and height of first pod insertion. The methods of optimization of Tocher, nearest neighbor and graphic dispersion of the canonical variables were consistent with each other. The characteristics number of days for the maturation (39.49%), weigh of 100 seeds (26.56%) and number of days for flowering (13.59%) were the ones that more contributed to the genetic dissimilarity among the twelve cultivate tested. The presence of genetic variability allowed the identification of dissimilar cultivars and with high average for the studied characteristics. The hybrids BRSMG Garantia x DM 339 and BRSMG Garantia x MG/BR 46 (Conquista) are promising for obtaining segregating populations with superior variability.