云南、贵州玉米大斑病菌生理小种分化研究

摘要

Northern corn leaf blight, caused by fungus Setosphaeria turcica, is one of the most important diseases in Yunnan and Guizhou maize production areas.Eight races were identified from 45 isolates, namely 12, 13, 3N,123, 12N, 13N, 23N and 123N from Yunnan and 4 races named 123, 13N, 23N and 123N from Guizhou.The virulence frequencies of the isolates from Yunnan against the resistance genes Ht1, Ht2, Ht3 and HtN were 73.3％,73.3％, 90.0％ and 80.0％, respectively, and those from Guizhou were 80.0％, 80.0％, 100％ and 93.3％, respectively.The more complex the composition of resistance genes, the lower the virulence of the isolate population.The lowest virulence to composition of the four single resistance genes was 30.0％ and 53.3％ in Yunnan and Guizhou, respectively.But the races in Yunnan were more complex than in Guizhou and the isolate virulence was higher in Guizhou than in Yunnan.%玉米大斑病是云南和贵州省玉米生产的重要病害之一.本文对2008年和2009年在云南、贵州采集分离获得的45份大斑病病菌菌株进行了生理小种鉴定,结果在云南共鉴定出12、13、3N、123、12N、13N、23N、123N等8个生理小种,其中123N小种出现频率最高,为30%;在贵州共鉴定出123、13N、23N、123N等4个生理小种,其中123N小种是主要小种类群,占53.3%.云南的大斑病菌菌株对Ht1、Ht2、Ht3和HtN基因的毒性频率分别为73.3%、73.3%、90%和80%,而贵州的菌株则分别为80%、80%、100%和93.3%.两省菌株的毒性随着抗性基因组合的复杂性增加而下降,对4基因组合的毒性频率分别为30%和53.3%;贵州的菌株毒性较云南菌株为高.云南的小种构成较复杂,而贵州小种的毒性更强.