水稻白叶枯病菌致病力的变异问题,日本最先有过报导,这是由于1957年福冈县等地种植的抗病品种“朝风”突然丧失抗性而引起的.其后鹫尾(1966)、Buddenhagen(1969),以及南京农学院和我所等(1976～1978)在这方面进行的研究都表明:白叶枯病菌不同菌株间的致病力确有不同,但只是数量上的差异,没有质(小种)的区分,所以一些抗性不同的品种,对不同菌株的互作反应,只表现水平梯度的连续性差异.因此,六十年代至七十年代初,东南亚国家一般都把白叶枯病菌 The variation of the virulence of bacterial blight in rice was first reported in Japan as a result of the sudden loss of resistance of the resistant variety “Asteroid” planted in Fukuoka Prefecture in 1957. Subsequently, 1966), Buddenhagen (1969) and studies carried out in this area by Nanjing Agricultural College and our institute (1976-1978) all showed that the pathogenicity of different strains of X. oryzae is indeed different, but only in quantitative Differences, there is no quality (races) distinction, so some varieties of resistance, interaction of different strains, showing only the continuity of the horizontal gradient differences.Therefore, the sixties to the early seventies, Southeast Asian countries in general All of the bacterial blight