Gene mapping of brachytic stem and its effects on yield-related traits in soybean

Abstract

Plant height, determinate growth habit, and brachytic stem are 3 major plant-type traits of soybean. In this report, a population of 151 recombinant inbred lines (RILs) derived from the cross of Bogao (high stature, indeterminate growth habit, and normal stem) and Nannong 94-156 (short stature, determinate growth habit, and brachytic stem) was used to map genes and quantitative trait loci (QTLs) for 3 plant-type traits and to reveal the effects of brachytic stem on yield-related traits including seed yield, apparent biological yield, apparent harvest index, plant height, and days to maturity. The results indicated that brachytic stem (sb) and determinate growth habit (dt1) were mapped on linkage groups B2 and L, respectively. Two major QTLs related to plant height were detected and mapped on linkage group L near dt1, and 0.6 cM above the Sb locus on linkage group B2 across 2 years. These 2 QTLs explained 15.1% and 52.7% of the phenotypic variation, and decreased plant height by 9.2 and 17.6 cm, respectively. It was found that only one QTL was detected and mapped on linkage group L near dt1 across 2 years. Lines with brachytic stem had shorter plant height, lower biomass, yield, and harvest index, and essentially no differences in days to maturity when compared with normal stem lines.