YM型小麦温敏雄性不育系不育基因的QTL定位

YM型小麦温敏雄性不育系的不育基因被定位在1Bs染色体片段上,但已发现的相邻分子标记与该基因的遗传距离较大,达10 cM以上。为寻找与该基因连锁更紧密的分子标记,以YM型温敏雄性不育系ATM3314与恢复系中国春杂交的F2代200株为作图群体,从1Bs的22个SSR引物中筛选出5个在亲本和F2代中分离的SSR引物,构建了1个包含5个标记的1Bs局部遗传连锁图谱。结合F2代个体的育性调查,采用复合区间作图法在YM型温敏雄性不育系的1Bs染色体上检测到不育基因的1个主效QTL rfv1-1和1个微效QTL rfv1-2。rfv1-1位于SSR标记Xgwm18和Xwmc406之间,与两标记的遗传距离分别为6.0 cM和4.6 cM,LOD值为8.80,加性效应23.87,显性效应10.44,可解释表型变异的23.91%;rfv1-2位于Xwmc406和Xbarc8之间,与两标记的遗传距离分别为4.0 cM和3.4 cM,LOD值为3.10,加性效应17.59,显性效应5.99,可解释表型变异的7.78%。本研究初步定位了YM型小麦温敏雄性不育系1Bs染色体片段上不育基因的QTL,为进一步准确定位该基因奠定了基础。

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 1Bs chromosome with genetic distance to adjacent molecular markers more than 10 cM. To further locate this thermo-sensitive male sterile gene, we constructed a mapping population with 200 F₂ plants from the cross between ATM3314 and restorer line Chinese Spring. Twenty-two simple sequence repeat (SSR) markers distributing evenly on 1Bs were screened between the parents and the male sterile and fertile bulks, and five markers showed polymorphism. These markers were then tested in the F₂ population. A 1Bs partial linkage map with the five SSR markers was obtained and QTLs for the male sterility were detected using composite interval mapping method. One major QTL and one minor QTL were detected, which were designated as rfv1-1 and rfv1-2, respectively. QTL rfv1-1 was located between the SSR markers Xgwm18 and Xwmc406 on chromosome 1Bs with genetic distances of 6.0 cM and 4.6 cM, respectively. The LOD value for this locus was 8.80, and the gene effects were 23.87 for additive effect and 10.44 for dominant effect. This QTL explained 23.91% of the phenotypic variation. QTL rfv1-2 was mapped between markers Xwmc406and Xbarc8 with genetic distances of 4.0 cM and 3.4 cM, respectively. The LOD value of this QTL was 3.10. This locus had additive effect of 17.59 and dominant effect of 5.99, and explained 7.78% of the phenotypic variation. These results are propitious for fine mapping and positional cloning of this male sterile gene.