小麦品种百农64慢白粉病抗性QTL的定位

QTL Mapping for Slow Mildewing Resistance in Chinese Wheat Cultivar Bainong 64

【目的】发掘慢白粉抗性基因及其紧密连锁的分子标记,为培育抗中国小麦主要病害白粉病的慢病性小麦品种奠定基础。【方法】利用100个SSR标记和58个AFLP标记,分析百农64×京双16组合218个F2:3系的基因型,构建由158个位点组成的遗传连锁图,在小麦连锁群上覆盖3 114 cM。2003～2004和2004～2005年度将该群体种植于北京和安阳两点,鉴定各个家系对白粉病的抗性。采用复合区间作图法进行慢白粉病的QTL分析。【结果】发现3个控制慢白粉病的QTL,其中位于2B和2D染色体的2个QTL在两种环境下均能检测到,贡献率分别为9.6%～11.3%和21.2%～26.1%。QTL遗传效应表现为加性和部分显性,其抗病等位基因均来自抗病亲本百农64。【结论】所得3个分子标记可作为选育慢粉性小麦品种的重要分子标记辅助选择工具。

[Objective] Powdery mildew is one of the most serious wheat diseases in China. Identification of slow mildewing resistance genes and their closely linked molecular markers is very important for developing durable resistant wheat cultivars. [Method] An F2：3 population with 218 lines derived from cross between Bainong 64 and Jingshuang 16 was sown with three replicates in Beijing and Anyang, Henan Province. Inoculation was carried out with the isolate E20 ofB. graminis f. sp. tritici before stem elongation, and disease severity to powdery mildew was scored for 4 times until the leaves were physiologically mature in Beijing during 2003 - 2004 and 2004 - 2005 cropping seasons. In Anyang, the disease was evaluated around May 18, in 2004 - 2005 cropping season under natural inoculation. A total of 100 SSR markers and 58 AFLP markers were used to construct a linkage map, covering 3114 cM of wheat linkage groups except chromosome 1D. [Result] With the method of composite interval mapping （CIM）, three QTLs were found on chromosomes 2B, 2D and 4D, in which the QTLs on chromosomes 2B and 2D were detected across two environments, accounting for 9.6% - 11.3% and 21.2% - 26.1% of phenotypic variance, respectively. The QTLs showed additive and partially dominant effects, which were derived from the resistant parent Bainong 64, [Conclusion] The molecular markers identified in this study will benefit for marker-assisted selections and pyramiding powdery mildew resistance genes to wheat breeding programs.