水稻白叶枯病菌(Xanthomonas oryae(Uyeda et Ishiyama)Dowson]存在致病力的差异。国内外的研究结果,有的认为病菌的不同的菌株其变异型是连续性的,为数量上的差异,有的则认为不同的菌株与水稻品种间的互作为垂直性的,存在质的差异。方中达等骨对我国各地280个白叶枯菌株进行致病性变异的测定,发现不同菌株的致病力强弱为连续性的差异,并初步区分为4个菌系群(Ⅰ—Ⅳ),1977—1978年我们以选用的鉴别品种测定湖南各地共30个白叶枯菌株的致病力,得到相似的结果广东报道该省的菌株致病力也为量的差异。考虑到上述这些结果不一致,既与不同研究用的鉴别方法以及不同菌株来源有关,也与鉴别品种的选择和供测菌株的数最有关,因此1981年我们增加了供测菌株的数量,并根据过去测定的结果,选用国内鉴别品种(即方等提出的鉴别品种)加上湖南省培育 There are differences in pathogenicity of Xanthomonas oryae (Uyeda et Ishiyama) Dowson.According to the research results both at home and abroad, some variants of different strains of pathogenic bacteria are considered as continuous and quantitative differences, Some believe that the interaction between different strains and rice varieties is vertical, there are qualitative differences.Fang Zhongda isobaric bone isolates from 280 strains of pathogenicity were measured in our country and found that different strains of The pathogenicity was the difference of continuity, and was initially divided into four strains (Ⅰ - Ⅳ). From 1977 to 1978, we used the selected varieties to determine the pathogenicity of 30 strains of B.cerevae in Hunan Province. Similar results have been reported in Guangdong Province, the pathogenicity of the strains is also the amount of differences. Considering these inconsistent results, both with different research methods and identification of different strains of origin, but also with the identification of species selection and testing of strains The number of the most relevant, so in 1981 we increased the number of strains for testing, and based on the results of the past test, the selection of domestic varieties (ie, Fang and other identified varieties) plus Hunan Province nurture