结合苗圃鉴定和ＲＡＰＤ分析，研究了稻瘟病菌继代培养过程中遗传的稳定性。结果表明，在继代培养过程中，强致病菌ＤＮＡ水平上变化较大，其致病性的变异也相当大，而弱致病菌ＤＮＡ水平上的变化较小，其致病性也无明显变异，说明强致病菌较弱致病菌更不稳定，其毒力在继代过程中有逐渐弱化的趋势，ＤＮＡ水平上的变化在一定程度上也反映了这种变异。 Combined with nursery identification and RAPD analysis, the genetic stability of Magnaporthe grisea subculture was studied. The results showed that in the process of subculture, strong changes in the DNA level of pathogenic bacteria, the pathogenicity of the variation is quite large, but weak pathogenic DNA changes in the lesser pathogenicity nor The obvious variation indicates that the pathogenic bacteria with stronger pathogenic bacteria are more unstable, and the virulence tends to weaken gradually in the process of subculture. The change of DNA level reflects this variation to a certain extent.