Selection of early soybean inbred lines using multiple indices

Abstract

Soybean [Glycine max (L.) Merr.] has been studied and enhanced for most of its economically important traits. Previous research has studied the association among them and the effect of the genotype × environment interaction; however, less is known about their correlation considering absolute maturity, as well as the use of multiple selection indices to study the genotype × environment interaction and select superior cultivars. Regarding this, the aim of the present study was to identify lines that associate precocity, good yield performance, and high oil and protein contents in the grains, as well as to estimate the correlation among these traits and study the effect of genotype × environment interaction using a standardized multiple selection index. Trials were conducted in two crop seasons in the state of Minas Gerais, Brazil, with 39 lines in 13 evaluation environments. The experiments were conducted in a randomized complete block design with four replications, and the grain yield, absolute maturity, and oil and protein contents in the grains were evaluated. The results indicated high experimental precision and accuracy, with significant differences among lines for all traits. High-magnitude correlations between evaluated traits were found, highlighting the negative correlation between absolute maturity and protein content in the grains. The genotype × environment interaction was also significant, and the use of the multiple selection index was efficient to identify superior and stable inbred lines by the genotype + genotype × environment (GGE) biplot method, which explained 82.23% of the genotype × environment interaction effect. Lines 27 and 31 stood out from the others because they associated stability and good performance for all evaluated traits.