QTLs and epistasis for drought-tolerant physiological index in soybean (Glycine maxL.) across different environments

The additive and epistatic effects and their genotype × environment (GE) effects on percentage gain with physiological traits under different environments were analyzed in soybean. The genetic characters of physiological traits in soybean and characters of quantitative trait loci (QTL) detected in different environments are discussed. A backcross inbred line (BIL) population of soybean derived from the cross of strong drought tolerant wild soybean, “SNWS0048” as a recipient parent and drought-sensitive variety “Jinda73” as a donor parent was examined to identify the QTL and epistatic QTL and GE effects on drought-tolerant physiological traits in Shanxi, China, in 2008 and 2010. Six QTLs with additive (a) effects and/or additive × environment interaction (ae) effects and three pairs of QTLs with additive × epistatic main (aa) and/or epistasis × environment interaction (aae) effects were detected in different water environment over two years. Six QTLs with aeffects and/or aeeffects were mapped to linkage groups D2, G, M and N. Among them, there were two QTLs without aeeffects, one with aeeffects in all four environments, two QTLs with aeeffects in two environments and one QTL with aeeffects in only one environment. Among three pairs of QTLs, one pair was identified with aaeffect and aaeeffect, one pair only exhibited aaeffect, and one pair only had aaeeffect without aaeffect. These indicated that different water environments could affect the expression of genes relevant to drought tolerant traits.