普通小麦品种Brock抗白粉病基因分子标记定位

为明确利用Brock转育成的小麦抗白粉病品系3B529(京411*7//农大015/Brock, F₆)抗性的遗传基础，将高感白粉病小麦品系薛早和3B529杂交，获得F₁代、F₂分离群体和F_2:3家系。抗病性鉴定和遗传分析结果表明，3B529对E09小种的抗性受1对显性基因控制，暂被定名为MlBrock。利用BSA和分子标记分析，获得了与MlBrock连锁的3个SSR标记Xcfd81、Xcfd78、Xgwm159和2个SCAR标记SCAR203和SCAR112，根据SSR和SCAR标记在中国春缺体四体、双端体和缺失系的定位结果，将MlBrock定位在小麦染色体臂5DS Bin 0~0.63区间上。MlBrock与Xcfd81和SCAR203共分离，与SCAR112的遗传距离为0.5 cM。这些分子标记的建立有利于今后Brock抗白粉病基因分子标记辅助选择和基因聚合。综合抗白粉病基因MlBrock的染色体定位和抗谱分析结果，推测MlBrock很可能是Pm2基因。

Molecular Identification of a Powdery Mildew Resistance Gene from Common Wheat Cultivar Brock

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most important diseases of common wheat (Triticum aestivum L.) worldwide. Common wheat cultivar Brock introduced from UK is highly resistant (IT: 0;) to powdery mildew prevalent isolate E09 at the seedling and adult plant stages in North China. Genetic analysis using an F₂ segregating population and F_2:3 lines, derived from a cross between susceptible common wheat lines Xuezao and resistant common wheat line 3B529 (Jing 411*7//Nongda 015/Brock, F₆), indicated that a single dominant gene, temporarily designated MlBrock, was responsible for the resistance of 3B529. By bulked segregant and molecular marker analyses, three polymorphic SSR markers (Xcfd81, Xcfd78, and Xgwm159) and two SCAR markers (SCAR203 and SCAR112) were found to belinked to MlBrock. Among these markers, Xcfd81 and SCAR203 were cosegregated with MlBrock, and SCAR112, Xcfd78, and Xgwm159 were linked to MlBrock with genetic distances of 0.5, 5.5, and 12.7 cM, respectively. According to the available physical bin mapping result of MlBrock cosegregated SSR marker Xcfd81 and SCAR203 in Chinese Spring, MlBrock was further located on chromosome bin 0–0.63 of 5DS. According to the infection-type of E09 Bgt isolate and mapping results, MlBrock might be powdery mildew resistance gene Pm2. The molecular markers developed in this study are useful for marker-assisted selection (MAS) and gene pyramiding of powdery mildew resistance genes in wheat breeding programs.