Seleção de linhagens de soja precoce para produtividade e qualidade de grãos

Abstract

The evaluation of soybean lines performance in the final stages of an plant breeding program is carried out by Cultivation and Use Value (CUV) tests, and it is an important step since it allows to select genotypes that associate good agronomic attributes, besides providing subsidies for recommendation of cultivars through the study of genotypes by environments interaction. In this context, the use of multiple selection indexes consists in a good alternative to consider several characters simultaneously throughout the evaluations, allowing the identification of superior genotypes and associating characters of interest. The study of the association between characters also allows a better understanding of the relationships between them, and thus increase success with selection. Thus, the present work aimed to identify soybean lines that associate precocity, good yield performance and high oil and protein contents in the grains, as well as to estimate the correlation between these traits and to study the effect of genotypes by environments interaction, using a standardized multiple selection index. The trials were conducted in the agricultural years 2014/15 and 2015/16 on Minas Gerais state, using a randomized complete block design with 39 lines in 13 evaluation environments, considering the combination of local and agricultural years. The characteristics of grain yield, absolute maturation, and oil and protein contents in the grains were evaluated. Correlations between these characters were also estimated. The soybean lines were analysed considering two multiple selection indices, and the study of genotypes by environments interaction was performed using the GGE Biplot method, using the standardized multiple selection index (SMSI). The results obtained allowed to infer that there is a positive and high magnitude association between grain yield and absolute maturation, as well as negative and high magnitude association between productivity and protein content, absolute maturation and protein content and between the contents of oil and protein in grains. The standardized multiple selection index was efficient in the study of the genotypes by environments interaction using the GGE Biplot method. The commercial cultivars 4 and 5 stood out from the others because they associated good attributes such as precocity, good productivity and grain quality.