中文摘要：

监测具有潜在威胁的小麦秆锈病病原菌小种动态并分析其毒力谱变化,是培育抗病品种不可或缺的基础工作。在小麦秆锈病鲜有发生的情况下,于2012–2013年获得小麦田间秆锈病标样11份和经有性生殖过程的禾柄锈菌小麦专化型菌样22份。上述菌样经过分离、纯化,得到了53个单孢子堆菌株。利用国内最新采用的禾柄锈菌小麦专化型小种与毒力鉴别寄主体系进行分析,鉴定出13个生理小种,其中34C3RTGQM和34Oro II-MRGQM为优势小种,出现频率均为13.2%,首次发现了对Sr5＋Sr11具有联合毒力的6个新小种,其出现频率处在1.9%–13.2%范围内。同时测定出Sr9e、Sr26、Sr31、Sr33、Sr37、Sr38、Sr47和Sr Tt3等8个抗秆锈病单基因对全部供试菌株表现抗病,余下40个单基因系则分别表现对1个以上至全部菌株感病。结论：（1）首次报道了6个对Sr5＋Sr11具有危险性的联合毒力谱的新小种类型,这类毒力类型应当被密切关注;（2）明确了当前完全有效的8个抗秆锈病基因和其他部分有效的抗病基因;（3）初步说明了有性循环菌株与无性循环菌株在毒力结构上存在差异。

英文摘要：

To monitor race dynamics and virulence spectrum variation of Puccinia graminis f. sp. tritici（Pgt） is a basic and very essential work to wheat breeding for rust resistance. In spite of difficulty in finding or gaining samples in wheat fields, a total of 33 natural accessions including 11 asexual and 22 sexual ones were collected in 2012–2013. After isolation and purification from these accessions, 53 isolates including 23 asexual and 30 sexual ones were obtained. A newly established differential host systemwhich possessed new function of discriminating Ug99 lineage was used for race and virulence characterization of the stem rust fungus. Four clusters or 13 physiological races were identified. Races 34C3 RTGQM and 34 Oro II-MRGQM were the most prevalent with 13.2% occurrence frequency and race 34 MRGQM secondly with 11.3% occurrence frequency. Six new races（34Oro II-MTGSM, 34 Oro II-MRGQM, 34 MRGQM, 34C3 RTGQM, 34 MTGSM and 34MRGSM） virulent to Sr5＋Sr11 were found for the first time in China with occurrence frequencies of 1.9%–13.2%. The result of virulence spectrum characterization had shown that the single genes of Sr9 e, Sr26, Sr31, Sr33, Sr37, Sr38, Sr47 and Sr Tt3 were all highly resistant to the tested isolates and the remainder 40 single Sr-gene lines were susceptible to at least one to all of the test isolates respectively. It is concluded that（1） the six new but dangerous races virulent to Sr5＋Sr11 should be on the alert;（2） the single gene lines of Sr9 e, Sr26, Sr31, Sr33, Sr37, Sr38, Sr47 and Sr Tt3 are all effective, while those of Sr22, Sr35, Sr Tmp, Sr30, Sr17 and Sr36 effective to most isolates and the remainder 34 lines have largely or totally lost their resistance;（3） the virulence structure of sexual cyclic isolates is different from that of asexual cyclic ones.