东北地区2009年玉米大斑病菌生理小种鉴定与动态分析

利用含Htl、Ht2、Ht3和HtN抗性基因的玉米自交系作为鉴别寄主,对2009年采自于辽宁、吉林、黑龙江省28个地区的113株玉米大斑病菌(Exserohilum turcicum)进行生理小种鉴定和种群动态分析。共鉴定出0、1、2、3、N、12、13、1N、2N、123、12N和123N号12个生理小种,有能克服单抗性基因的小种,也有能同时克服4个抗性基因的强致病性小种,生理小种组成趋于多元化。其中,0号和1号小种为优势小种,分别占供试菌株的47.8%和19.5%。所鉴定的113个菌株对抗性基因Ht1、Ht2、Ht3和HtN的毒性频率分别为37.2%、21.2%、4.4%和15.9%。研究结果表明,东北地区玉米大斑病菌生理分化明显,生理小种的分布与种间的变异频率趋于复杂化。玉米大斑病菌0号和1号小种以外其他生理小种出现频率升高和品种抗性的丧失是玉米大斑病发生的重要因素。

Identification and Dynamic Analysis on Physiological Race of Exserohilum turcicum in Northeastern China in 2009

The physiological race of Exserohilum turcicum was identified among 113 isolates collected from 28 areas of Liaoning, Jilin and Heilongjiang provinces in 2009 on maize inbred lines with Ht1, Ht2, Ht3 and HtN resistance genes, and its population dynamics was investigated. The results showed that 12 races were identified among these fungal isolates, including 0, 1, 2, 3, N, 12, 13, 1N, 2N, 123, 12N and 123N. Those races can not only infect the maize with single Ht gene, but also that with all kinds of resistance gene, and it meant the race component was in pluralistic. Among these races population, races 0 and 1 were predominant with occurrence frequency of 47.8% and 19.5%. The virulence frequencies against genes Ht1, Ht2, Ht3 and HtN were 37.2%, 21.2%, 4.4% and 15.9%, respectively. The physiological differentiation of E. turcicum was obvious, and their distribution and inter-specific variability also became complex. The increasing epidemic of northern maize leaf blight in northeastern China was ascribed to the increasing virulence frequencies of such major races as 0 and 1, and the resistance losing of the cultivars.