QTL Mapping For Sitodiplosis Mosellana (Géhin) Resistance In Bread Wheat (Triticum Aestivum L.)

Wheat blossom midge(Sitodiplosis mosellana Géhin) has imposed important influence on wheat production worldwide. The orange wheat blossom midge(OWBM) larvae feeds with the filling kernel, as led to shrivelled grains and resultant yield losses. Breeding wheat varieties conferring resistance to OWBM is the most effective and environment-friendly way to control midge and resultant yield losses. In present study, a recombinant inbred line(RIL) population derived from the cross between wheat accessions “Henong 215” and “Yanyou 361” was used to map the QTLs for midge resistance during 2012-2014 seasons. Conditional and unconditional QTL methods were used to reveal the relationship between the main agronomic traits and OWBM resistance. The main results are as follows:1. Recombinant inbred line(RIL) population with 388 lines was produced from the cross between wheat accessions “Henong 215” and “Yanyou 361” with single seed descent method from F2 generation and was used to construct linkage map. “Henong 215” showed highly resistant to midge, while “Yanyou 361” was highly susceptible to midge. The linkage map consisted of 148 SSR markers, with a total genetic distance of 1651.3c M and the average distance between markers of 11.23 c M. For each linkage group, the coverage variated between 1.5c M and 153.5c M, and the average distance between markers was between 1.5c M and 37.0c M. Chromsome 5B can not be constructed. For the lack of markers anchored, markers on three linkage groups can not be linked, and be named as Chr1, Chr2 and Chr3.2. During the experimental seasons, a total of three QTLs, QSm.hbau-4D, QSm.hbau-2B, QSm.hbau-4A and were related to midge resistane. Among them, QSm.hbau-4D can explain the phenotypic variation of 11.38%.3. In the two seasons, twenty-one QTLs, which were located on chromosomes 5A, 6A, 7A, 1B, 3B, 5B, 2D, 3D and 4D, were related to six agronomic traits detected. Among the QTLs, phenotypic variation explained ranged from 3.31% to 44.29%, with maximum LOD value of 42.32. No QTLs contributed to spikelet numbers, heading date and duration from heading date to flowering date, were detected.4. No newly QTLs were recovered, when using estimated loss rate(ELR) as index to detect conditional QTLs for midge resitance with plant height, stem length under spikeand duration from heading to flowering date, but the additive effect of QTLs on chromosomes 4D was reduced, which indicated some of the wheat midge resistance in present study was related to agronomic traits.