Potential of recurrent selection for soybean improvement

Abstract

South region of Minas Gerais state has been emphasizing in the last years in the soybean crop. However, there are still few breeding works that aim to develop specific cultivars for this region. In the soybean breeding, several agronomic attributes have been studied by the breeders in order to release superior cultivars. Among the main traits can be highlighted grain yield and full maturity. These are quantitative. When it is desired to perform the plant breeding for one or more traits, controlled by several genes, it is impossible to succeed in a single selective cycle. The main alternative is recurrent selection. Although recurrent selection has been proposed for cross-pollinated crops, it has been widely used in the autogamous plants breeding. In the case of soybean, there are reports of the use of recurrent selection abroad for protein content in grains. However, a recurrent selection program aimed for soybean grain yield is unprecedented in Brazil. Thus, the purpose of this work was to estimate genetic and phenotypic parameters associated to the progenies of the recurrent selection program for grain yield in soybean at UFLA; and to select genetically superior progenies, with good agronomic attributes for the southern region of Minas Gerais / Campo das Vertentes. S0:1 progenies were evaluated in the municipality of Lavras, 2015/2016 crop season. The S0:2 progenies were evaluated in the next crop season,2016/2017, in the municipalities of Lavras, Nazareno and Itutinga. Were evaluated the traits: days for flowering, full maturity, height of insertion of the first pod, height of the plant, lodging score and grain yield. The data were analyzed using the mixed model approach. The estimates of the components of variance show the existence of variability among the progenies making possible the selection of superior genotypes. The evaluated progenies present good agronomic performance. When selecting the highest grain yield progenies, there was an increase in the values of full maturity, days for flowering, height of plants and height of insertion of the 1st pod. Recurrent selection is a promising strategy for the improvement of soybeans in Brazil, not only for the ability to generate superior cultivars, but also for reducing the complexity of conventional breeding programs.