Seleção de linhas puras na cultivar de soja BRS favorita RR

Abstract

In spite ofcultivars of autogamous plants are homogeneous lines, the use of grain as “seeds” by the farmers and the successive cultivation may generate natural variability due to mechanical mixing, natural hybridization and mutation. Although this variability is not being explored in soybean crops, it is possible to apply the selection of pure line methods in order to obtain new cultivars. The estimation of genetic and phenotypic parameters allows making inferences about the existence of genetic variability, as well as measuring the gain with the selection of the superior genotypes. In this context, the present work had as objective to estimate the genetic and phenotypic parameters, as well as to identify and select superior genotypes that associate good performance in characters of interest from a heterogeneous population of the soybean cultivar BRS Favorita RR. The 225 plants were collected from a rural propriety in Itutinga – MG, where soybean cultivation has been reported for several years, saving seeds. The experiments of evaluation were carried out during the crop years of 2014/2015 and 2015/2016, in five cities in Minas Gerais State, in simple and triple lattice with 255 and 80 progenies, respectively, plus BRS Favorita RR, as a check. The agronomic characters: plant height (cm), first pod insertion (cm), maturation (cm), lodging (1-5 scale), grain yielding (sc/ha) were evaluated. The analysis of the obtained data was performed in the statistical software R using mixed models approach. Afterwards, the genetic parameters, the expected gain with selection and the gain realized in the selection intensities of 1%, 5%, 10%, 15%, 20%, 25%, and 30% were estimated,besides the frequency distribution of the adjusted means and errors associated to the genotypic values. The estimates of variance component among progenies were significant showing that there is difference between the treatments. From the frequency distribution, it was possible to verify the possibility of selecting progenies that overcome the check for all characters. The progeny 22 was highlighted ad the most productive. From these results, it was possible to verify that the existence of variability in the heterogeneous BRS Favorita RR allows the selection of lines that associate good grain yielding, plant height, first pod insertion and tolerance to lodging superiors to itself.