云南省玉米小斑病菌生理小种的初步鉴定

Preliminary identification of physiological races of Bipolaris maydis in Yunnan

从云南省13个地区42个县(市)采集玉米小斑病样本,分离出113个单孢菌株,并在中国鉴别品种上开展了生理小种鉴定.结果表明,玉米小斑病菌生理小种O,C,S和T小种在云南省均有分布,O小种是优势小种,且O小种菌株具有不同致病力,中等致病力菌株和弱致病力菌株频率明显高于强致病力菌株.此外,生理小种类型在不同海拔上分布存在差异,S小种多分布于高海拔地区.

One hundred and thirteen isolates of Bipolaris maydis,collected from 13 prefectures including 42 counties or cities in Yunnan,were identified based on their pathogenic types on the Chinese Differentials.The results showed that 4 physiological races O,S,T and C existed in Yunnan,and among them Race O was dominant and had different pathogenicities.Medium and weak pathogenic isolates of Race O was significantly more than those of the strong one.Besides,there was discrepancy about distribution of physiological races of B.maydis at different altitudes,especially Race S distributed at high altitude.