玉米大斑病菌的生理小种及交配型测定

试验对采自2003年我国部分玉米产区的大斑病菌17个标样进行了分离并对其生理小种进行了鉴定。结果发现,我国的大斑病菌生理小种种类繁多,出现了0、1、2、3、N、12、23、123、13N、23N、123N共11种类型,尽管0、1号生理小种仍为优势小种,但出现的频率尚不到20%。在此基础上利用菌株对峙杂交法测定了其交配型,发现A、a和Aa共3种交配型,且交配型为Aa的两性菌株所占比例最大,占47.06%,比以前大幅度提高,说明随着我国耕作制度的改革和品种的更换,生理小种和交配型的变化出现了多元化。

Identification of Physiological Races and Mating Type of Exserohilum turcicum

Seventeen Exserohilum turcicum isolates collected from six major corn-planting provinces in 2003 using inbred Huangzao 4 without or with Htl, Ht2, Ht3 and HtN resistant gene respectively as differentiation hosts had been identified. The experimental results showed that more than 11 physiological races including 0, 1, 2, 3, 12, 23, 123, N, 13R, 23R, 123N appeared and race 0 and 1 were also the dominant ones but their appearing frequency were less than 20%. Based on these, mating type of all the seventeen isolates were also studied and it showed that there were three mating types including A, a and Aa, and more important thing was the frequency of mating type Aa was to 47.06% and much higher than before. It was conclusion that both physiological races and mating types became multi-complex with the change of plantation and corn varieties in China.