新鉴别寄主和改进的分析方法在叶锈菌小种研究中的试用

New Differential Hosts and Improved Method of Analysis in the Study of Leaf Rust of Wheat in China (1987—1988)

本研究对原有的叶锈菌的鉴别寄主进行了调整,用与当前生产有关的品种和抗原来代替与生产无关的品种。对小种命名也进行了改进,对基因型不明的鉴别寄主用R1—RN来标志,对能克服这些寄主抗性的菌株用对应的V1—VN来标志,使小种命名可带有遗传学涵义。本年度共鉴定了来自全国9个省(区)的410个菌株,用新鉴别寄主鉴定小种,可以直接反映当前用的重要小麦抗源和品种与叶锈菌的相互关系。结果表明,对洛夫林10,山前麦等重要抗源有毒力的洛10小种群在进一步发展,出现频率达51.7%,比1985—1986年度的21.2%上升了30.%。应引起育种部门的严重注意。毒力频率分析可以了解品种与锈菌群体的关系。结果表明,新鉴别寄主中除百农3217的毒力频率值为20.7%表现抗性较好外,其它重要品种和抗源的毒力频率值达34.6—51.7%,说明当前叶锈菌的群体毒力较高和品种的抗性不理想。叶锈菌的毒力组合频率和新鉴别寄主的抗性组合频率分析,可以了解品种群体与锈菌群体的关系,可以了解最佳的品种组合对防病效果最好。

The original set of differential hosts has been adjusted by using the important sources of resistance in breeding program and the important commercial cultivars to replace the hosts which are not relevant to agriculture. The method of designating hosts and races has also been changed. The hosts of unkown genotypes are designated as R_1-Rn and the races which are virulent to these hosts are correspondingly designated as V_1-Vn respectively.Four hundred and ten isolates of Puccinia recndita f.sp.tritici collected from 9provinces have been identified by using both old and new differentials for comparison. There are 9prevalent races identified among which the Lovrin 10 race group which threatens the important source of resis tance has increased to 51.7%. Its frequency of occurrence has increased 30.5% as compared with the result of survey made during 1985—1986.Analysis of the interaction of hosts and the population of rust has revealed that except the virulence frequency of the rust to host Bai Nong 3217 be 20.7% which is the lowest, all the virulence frequency of the rust to other hosts are 34.6—51.7%, indicating higher virulence of race group of exsisting leaf rust and less ideal sources of resistance of commercial cultivars.The analyses of virulence association of the pachogen and the resistance association of the host have also been made. The best combined effect of resistance can be predicted by selecting the best possible combination of hosts.Discussion has stressed on gene determination instead of race determination in further improvement in rust work.