Capacidade combinatória, diversidade genética e correlações em soja ; Combining ability, genetic diversity and correlations in soybean

The choice of genitors for the formation of segregating populations in crosses is an extremely important step for breeding programs. The estimation of genetic components allows the identification of favorable hybrid combinations and, consequently, the obtaining of superior populations. Thus, the objective of this study was to estimate the general combining ability (GCA) and specific combining ability (SCA) of four parents in order to verify more favorable hybrid combinations for obtaining populations for selection of promising progenies for grain production and agronomic characters of importance. The experiment was carried out in a greenhouse of the Soybean Breeding Program, at Capim Branco farm of the Federal University of Uberlândia. For diallel analysis, four parents were adopted (BRS 263, TMG 4185, TMG 803 and UFUS Guará) and their six F1 hybrids were evaluated in a randomized complete block design with four replications. Each plot consisted of a pot cultivated with two plants. The following characters were evaluated: number of days to flowering and to maturity, plant height at flowering and at maturity, number of nodes at flowering and at maturity, height of first pod insertion, number of pods with one, two and three grains, total number of pods per plant, number of grains per pod and grain yield per plant. The genetic-statistical analysis was carried out using the Griffing methodology (1956), method 2. The parent UFUS Guará has favorable alleles for reducing the number of days to maturation, which can be indicated for crosses aiming at reducing the cycle. Parents UFUS Guará and BRS 263 are prominent in breeding programs aimed at raising production components. The combinations UFUS Guará X BRS 263 and UFUS Guará x TMG 4185 showed potential for decreasing the cycle and increasing grain production by plants, showing the capacity for the development of promising segregating populations.The chapter three of this study consisted of evaluating the genetic dissimilarity between advanced soybean lines in two ...