中文摘要：

利用广谱抗稻瘟病基因Pi9基因序列设计的特异分子标记Pi9-a，通过回交育种和分子标记辅助选择技术，改良8份受体水稻材料（丰源B、1132B、天龙香103、香丰187、明恢63、轮回422、R747、25H003）的稻瘟病抗性。结果表明：分子标记Pi9-a对8份受体亲本与Pi9供体亲本75—1—127间进行的多态性检测中，除香丰187外，其余7个组合间均存在稳定明显的多态；对4个BC1F1群体进行随机取样的基因型和表型鉴定中，Pi9-a对抗稻瘟病表型选择的效率均为100％。

英文摘要：

In this study, a specific inner genic molecular marker Pi9-a was developed based on the sequence of the Pi9 gene, and was employed for improving the blast resistance of 8 receptor indica rice lines （FengyuanB, I132B, Tianlongxiang103, Xiangfeng187, Minghui63, Lunhui422, R747 and 25H003） through marker-assisted selection （MAS） and back-cross breeding. Pi9-a showed obvious and stable polymorphisms between the donor line of Pig, 75-1-127 and 8 receptor lines except Xiangfeng187. The individuals from 4 BC1FI populations were genotyped and phenotyped, and the result showed that the selection efficiency using Pi9-a was 100%.