Validation of the quantitative trait locus underlying soybean plant height using residual heterozygous lines and near-isogenic lines across multi-environments

Illustrating the consistency and pleiotropic effects of a quantitative trait locus (QTL) across multi-locations is important for breeding. In this study, a QTL qPH_6_1, underlying soybean plant height, was positioned on chromosome 6 using a BC2F5 family, which was developed using ‘Jidou 12’ as recurrent parent, and ‘Xinbada 2’ as donor parent. The residual heterozygous lines (RHLs) derived from BC2F5 plants that segregated at qPH_6_1 were used to validate and pinpoint the QTL at both locations. For RHLs, qPH_6_1 explained approximately 80% of the variance for plant height and number of nodes, and was positioned in a 3.5 cM interval co-segregated with Satt557, Satt489, Satt134 and Satt289. The analysis of near-isogenic lines, developed from RHLs, also showed that qPH_6_1 had a significant impact on plant height and number of nodes across the other ten locations in 2 years. A larger genetic effect was observed at locations in north China than in south. While, qPH_6_1 could only explain 1.6–30.4% of the phenotypic variation for 100-seed weight, protein content, oil content, and grain yield, and their effects varied with locations. The results provide information for breeding widely adapted soybean cultivars.