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在分别含Ｈｔ１、Ｈｔ２、Ｈｔ３和ＨｔＮ的单基因玉米鉴别寄主上测定了全国玉米各产区的百余份大斑病菌标样。结果表明，按传统方法命名的１号（或称０号）生理小种仍然是优势小种，占供试菌株的７３．０％；２号（１号）生理小种占１．９％。虽然未出现已报道的３号（２３号）、４号（２３Ｎ号）和５号（２Ｎ号）小种，但特别值得注意的是出现了２５．１％的未定名的新类群。为克服传统命名方法的局限性及指导抗病育种及品种布局，本文初步提出用毒力频率法分析玉米大斑病菌的生理分化状况，并进一步指明了不同致病类群在我国的分布频率及Ｈｔ基因的可用范围
A hundred samples of S. turcica were screened on single maize differential hosts containing Ht1, Ht2, Ht3 and HtN respectively. The results showed that the race 1 (or 0) named by the traditional method was still dominant races, accounting for 73.0% of the tested strains; race 2 (No.1) accounted for 1.9%. Although none of the reported race 3 (23), 4 (23N) and 5 (2N) races have emerged, it is particularly noteworthy that 25.1% of the unnamed new taxa have emerged. In order to overcome the limitations of traditional nomenclature and guide the breeding of disease resistance and variety distribution, the paper initially proposed the virulence frequency method to analyze the physiological differentiation status of S. turcica and further indicated the distribution frequency of different pathogenic groups in China and Ht The available range of genes