中文摘要：

由 Blumeria graminis f.sp.tritici 引起的小麦白粉病是危害甘肃省小麦安全生产的重要病害之一,分析病原菌毒性结构和抗病基因有效性对于指导白粉病的有效控制具有重要意义。2013年对甘肃省小麦白粉菌群体进行毒性分析结果表明,91个供试菌系中,对 Pm1、Pm2、Pm3a、Pm3b、Pm3c 、Pm3d 、Pm3e 、Pm3f、Pm4a、Pm4b、Pm5a、Pm6、Pm7、Pm8、Pm19、Pm33、Pm5＋Pm6、Pm4＋Pm8、Pm4b ＋Pm5b 和 PmEra 的毒力频率达到70%以上,已无利用价值；对 Pm13、Pm16、Pm21和 Pm24的毒性频率在15%以下,尚可利用。选用甘肃省不同毒性谱的单孢堆菌系,对35个甘肃省及国内生产品种（系）进行苗期致病性测定,发现仅有‘绵麦37’具有优异抗病性。供试白粉菌系对‘定西40号’等22个品种（系）的毒性频率达到60%以上,甘肃省及中国生产品种中,苗期抗病品种（系）匮乏。

英文摘要：

Powdery mildew caused by Blumeria graminis f.sp.tritici （Bgt）is one of the most important diseases that damage wheat production in China.It is important to control powdery mildew by analyzing virulence struc-ture and effectiveness of resistance genes.This study was conducted to test virulence structures of 91 isolates col-lected from Gansu Province in 2013.The results of virulence survey revealed that the virulence frequencies of the resistance genes Pm 1,Pm 2,Pm 3a ,Pm 3b ,Pm 3c ,Pm 3d ,Pm 3e ,Pm 3f ,Pm 4a ,Pm 4b ,Pm 5a ,Pm 6,Pm 7, Pm 8,Pm 1 9,Pm 33,Pm 5＋Pm 6,Pm 4＋Pm 8,Pm 4b ＋Pm 5b and PmEra reached more than 70%,respective-ly,indicating that these resistant genes could not be used as mildew resistance sources any more.The virulence fre-quencies of the mildew population tested to the resistance genes Pm 13,Pm 1 6,Pm 21 and Pm 24 were lower than 1 5%,and these genes could still be used in breeding for mildew resistance.By artificially inoculating 91 Gansu Bgt isolates with different virulent spectrum at seedling stage,the resistance to 35 wheat varieties from Gansu and oth-er provinces were evaluated.The results showed that only ‘Mianmai 37’was immune to all isolates,with a viru-lence frequency of 60% and more to 22 wheat varieties,including ‘Dingxi 40’.The resistant wheat cultivars in seedling stage were absent in Gansu Province and China.