河北省玉米小斑病菌生理小种鉴定及群体动态变化

Identification and Population Dynamics of Physiological Races of Bipolaris maydis in Hebei

1987～2003年从河北省10个地区采集玉米小斑病标样,对分离出的288个玉米小斑病菌菌株进行了生理小种鉴定。在鉴定的年度范围内,玉米小斑病菌T小种、C小种、S生理型与O小种的分离频率在地区间和年度间存在显著差异,O小种的平均分离频率明显高于其他小种,是河北省玉米小斑病菌的优势小种。在年度间,C小种的分离频率也存在显著差异,T小种、S生理型、O小种的分离频率无显著差异。O小种具有不同致病力,强致病力菌株和中等致病力菌株的出现频率较弱致病力菌株高,强致病力菌株主要分布在河北省的东部和南部,弱致病力菌株主要分布在河北省北部。

Samples of corn southern leaf blight were collected from 10 locations of Hebei province from 1987 to 2003. Among them, 288 strains of Bipolaria maydis were identified with the identification hosts. Results showed that isolation frequencies of Race T, Race C, Type S and Race O were significantly different from each other in respects of both locations and years. Isolation frequency of Race O was significant higher than those of the other races. It is suggested that Race O is the dominant race of B.maydis in the corn-growing area in Hebei province. During the identification period, the isolation frequency of Race C showed significantly different. The pathogenicity of Race O from different areas and years was different. The isolation frequency of strong pathogenic strains of Race O was more than that of the weak pathogenic strains. The strong pathogenic strains mainly distributed in the eastern and southern of Hebei, while the weak pathogenic strains mainly distributed in the northern of Hebei.