Mapping QTLs for Male Sterile Gene in YM-Type Thermo-Sensitive Male Sterile Line of Wheat

The sterile gene of YM-type thermo-sensitive male sterile wheat (Triticum aestivum L.) line has been mapped on chromosome arm 1BS, which was more than 10 cM distant from the adjacent molecular markers. For detecting markers with short distances to this gene, a population with 200 F₂ plants was constructed from the cross between ATM3314 and the restorer line Chinese Spring. Among 20 simple sequence repeat (SSR) markers distributing evenly on 1BS, 5 SSRs showed polymorphism between the parents and between the male sterile and fertile bulks. A 1BS partial linkage map carrying the 5 markers was obtained and QTLs for the male sterility were identified using composite interval mapping method. One major QTL and one minor QTL were detected and designated rfv1-1 and rfv1-2, respectively. QTL rfv1-1 (LOD = 8.80) was located between markers Xgwm18 and Xwmc406 with the genetic distances of 6.0 cM and 4.6 cM to the adjacent markers, respectively. On this locus, the additive and dominant effects were 23.87 and 10.44, respectively, which accounted for 23.9% of the phenotypic variation. QTL rfv1-2 (LOD = 3.10) was mapped between markers Xwmc406 and Xbarc8 with the genetic distances of 4.0 cM and 3.4 cM, respectively. This locus had additive effect of 17.59 and dominant effect of 5.99, and explained 7.8% of the phenotypic variation. These results are propitious for fine mapping and positional cloning of this male sterile gene.