Abstract: Fifty-seven mono-conidial blast fungi (Magnaporthe grisea) isolated from three main diseased areas of Hunan Province in September 2001 were co-cultivated on rice flour medium with four standard testers provided by International Center for Collaboration in Agronomic Research and Development (CIRAD) in order to determine their mating types. Results showed that 30% and 12% of the tested isolates were determined as Mat1.1 and Mat1.2, respectively, while the remaining 60% were unknown mating types. A total of 24 fertile strains were obtained, only five of them were female/hermaphroditic isolates, being accounted for 9% of the total tested isolates. The cross between isolates of the opposite mating types did not show any production of perithecia even between hermaphroditic isolates. The Chinese race of each isolate was determined after pathogenicity test to the seven Chinese differential cultivars. ZA and ZB were dominant groups and the race ZB15 was predominant among the 20 races obtained. The perfect stage of M. grisea in the field was also discussed.

Key words: Magnaporthe grisea, rice blast, hermaphrodic isolates, mating type, pathogenicity

摘要： 2001年9月在湖南省3个稻瘟病的主要发病县采集分离了57个稻瘟病菌株，与法国国际农艺研究和发展中心提供的4个标准菌株于稻谷粉琼脂培养基上对峙培养。结果表明，30% 和12% 的测试菌株分别为交配型1.1和交配型12，其余60% 的测试菌株与4个标准菌株中的任何一个均不能产生子囊果，即便是与田间新获得的两性菌株之间的对峙培养也不能产生子囊果。在所获24个能育菌株中只有5个为两性菌株,占9%。各菌株在中国7个鉴别品种上的测定共获5群20个小种，其中ZA 和ZB为优势群，ZB15为优势小种。还就稻瘟病菌有性世代在田间存在与否进行了讨论。

关键词: 稻瘟病菌, 稻瘟病, 两性菌株, 交配型, 致病性