中文摘要：

抗病品种和化学防治是控制植物病害最有效的两种措施,病原菌在长期选择压下可改变其群体结构,以逐步适应品种抗性和杀菌剂压力.本研究采用拌种离体叶段法对2012年采自我国9个省（市）的129个小麦白粉病菌Blumeria grami-nisf.sp.tritici单孢堆分离物进行了三唑酮敏感性检测,同时采用31个已知抗病基因品种（系）对其进行苗期毒性测定,并对二者之间的相关性进行分析结果表明：129个供试菌株对三唑酮的EC50为109.97 mg/L,平均抗药性水平达到52.62倍,变异系数为107.2.所有供试菌株中,99.22％的菌株产生了抗药性,其中高抗菌株占58.91％,中抗菌株占37.98％.北京菌株的抗药性水平明显高于其他8个省市.利用Popgen1.32软件对9个省（市）小麦白粉病菌群体的毒性多样性分析结果表明,四川群体毒性基因多样性水平最高,Nei基因多样性H值为0.224 1,浙江群体最低,H值为0.0968.小麦白粉菌群体对三唑酮的敏感性和毒性的相关性分析表明,EC50或EC50变异系数与毒性多样性之间均不存在显著的相关性,但EC50与毒性基因数目之间的关系符合对数方程.此结果可为杀菌剂和抗性品种的合理利用提供依据.

英文摘要：

Host resistance and fungicides are two of the main approaches used to control plant diseases in con- ventional agriculture. The widespread use of host resistance and fungicides selects for pathogen individuals or populations that can overcome the host defense systems or that are resistant to the applied fungicides. One hun- tired and twenty nine isolates of Blumeria graminis f. sp. tritici were collected from 9 provinces/cities in 2012, and inoculated onto 31 differential wheat lines of powdery mildew to test the virulence. The sensitivity of the iso- lates to triadimefon was tested by seed treatment and detached leaf segment methods. The correlation between virulence diversity and triadimefon-resistance was carded out by SAS software. The results showed that median ECso of isolates to triadimefon was 109.97 mg/L,the coeffective of ECho was 107.2,the mean resistance factor （RF） was 52.62.The resistant frequency of all isolates to triadimefon was up to 99.22%. The mean resistant fac- tors of B. graminis f. sp. tritici isolates from Beijing was higher compared to the other eight provinces. Virulence diversity of B. graminis f. sp. tritici isolates from Sichuan Province was highest with the index of virulence gene diversity 0.224 1. The virulence gene diversity of isolates from Zhejiang was lowest with the index 0.096 8. The association between triadimefon-sensitivity and virulence diversity of B. graminis f. sp. tritici isolates showed that there was no significant correlation among EC50, variation coefficient of ECs0 and virulence diversity. However,there is a logarithmic （r=0.240 4, P=0.009 6） relationship B. graminis f. sp. tritici isolates. These results may provide ance varieties, as well as the use of triazole fungicides. between ECho and numbers of virulence genes of 129 a reference for reasonable utilization of wheat resist-