Molecular Markers Associated with Water Use Efficiency and Leaf Ash in Soybean

Abstract

Water use efficiency (WUE) is an important trait that has been associated with drought tolerance of crop plants, and leaf ash (LASH) generally related to WUE. A restriction fragment length polymorphism (RFLP) map was constructed from a soybean [ Glycine max (L.) Merr.] population of 120 F4‐derived lines from a cross of ‘Youngș × PI416937. The purpose of this research was to identify quantitative trait loci (QTL) associated with WUE and LASH in 36‐d‐old, greenhouse‐grown plants. The experimental design was a randomized complete block with six replications. Significant ( P < 0.01) phenotypic differences were detected among the lines for both traits. A total of four and six independent RFLP markers were associated with WUE and LASH and if combined each group of markers would explain 38 and 53% of the variability in the respective traits. One marker locus (cr497‐1), on USDA Linkage Group J, explained 13.2% of the variation in WUE indicating the presence of a major QTL. The LASH was negatively correlated with WUE ( r = −0.40**), and two QTL were associated with both WUE and LASH. For each of these QTL, the allele for increased WUE was associated with reduced LASH.