Abstract: A doubled haploid (DH) population with 150 lines, derived from a cross between two common wheat varieties Hanxuan10 and Lumai14, was used in this research. Several root traits including root number (RN), maximum root length (MRL), root fresh weight (RFW), root dry weight (RDW), ratio of root fresh weight to shoot fresh weight (RFW/SFW) and ratio of root dry weight to shoot dry weight (RDW/SDW) per plant of hydroponic seedlings were measured under water stress and control conditions, respectively. Quantitative trait loci (QTL) and G×E interactions for these traits were detected using mixed-model-based composite interval mapping method. A total of 11 additive QTL and 15 pairs of epistatic QTL associated with root traits were mapped on all chromosomes except 5A, 4B, 2D, 6D and 7D. Among these QTL, 3 QTL with additive effects and 2 pairs of epistatic QTL controlling root number, 3 QTL with additive effects and 3 pairs of epistatic QTL controlling maximum root length, 2 QTL with additive effects and 2 pairs of epistatic QTL controlling root fresh weight, 2 QTL with additive effects and 3 pairs of epistatic QTL controlling root dry weight, 2 pairs of epistatic QTL controlling ratio of root fresh weight to shoot fresh weight and 1 QTL with additive effects and 3 pairs of epistatic QTL controlling ratio of root dry weight to shoot dry weight were detected. One additive QTL × environment and three pairs of epistatic QTL × environment interaction effects were also identified. The possibility of using marker-assisted selecting root traits and drought tolerance in wheat was discussed.

Key words: Wheat, Doubled haploid (DH) population, Root trait, Quantitative trait loci (QTL) mapping, G×E interaction