Abstract：Plant height is one of important agronomy traits affecting wheat yield with very high sensitivity of water environment. Known better the quantitative genetic and its interactions with water environments of plant height (PH) development in common wheat, conditional quantitative trait loci (QTLs) were studied for PH using a recombinant inbred lines (RIL) with 120 progeny lines, derived from a cross between Longjian 19 (drought tolerant) and Q9086(water sensitive)(Triticum aestivum L.). The PH phenotypes at different stages were evaluated under rainfed (drought stress, DS) and well-watered (WW) conditions in Zhenyuan and Lanzhou, Gansu Province, respectively. Conditional QTLs analyses were performed by a mixed linear model approach. The total of 26 additive QTLs (A-QTLs) and 56 pairs of epistatic QTLs (AA-QTLs) were detected for conditional PH of wheat at different growth stages in two locations. In all A-QTLs, six major loci, Qph.acs-1A-1, Qph.acs-4B-2, Qph.acs-5A-1, Qph.acs-5D-1, Qph.acs-6B-2 and Qph.acs-7D-1, were identified in repetition at pre-flowering stages, showed higher genetic contribution percentage (H2(A)) ranged from 7.39% to 31.04%. All of AA-QTLs for PH were mainly composed of interactions between different QTLs with non-significantly additive effects, explaining H2(AA) ranged from 1.38% to 24.27%. Those AA-QTLs significantly influenced the PH at later growth stages. 61.54% of A-QTLs and 58.93% of AA-QTLs were greatly interacted with water regimes. Under rainfed, genetic effects of water environmental interaction could decrease the PH. At the jointing stage, additive effects of conditional A-QTLs for PH showed higher than that of other stages. And then, additive effects were gradually decreased but more emphasized of epistatic effects. The result indicated that quantitative genes controlled the PH development could be easily interacted with water environments, proceeding to some temporal-spatial expressions at different growth stages in wheat. The information in this study can be useful for the molecular genetic improvement of drought tolerance in wheat
