Abstract：Intergenic spacer（IGS） was analyzed for 16 strains of powdery mildew using universal primers，which collected from melon，cucumber，pumpkin and watermelon on cucurbits in various regions of Heilongjiang Province．The results showed that there were length heterogeneity and polymorphism on IGS．IGS-RFLP digested by MspⅠ，AsuⅠand Hin p1Ⅰshowed that digest sites varied from the strains with profile polymorphism．The IGS-RFLP profile could become distinctive DNA fingerprint for strains．On the basis of IGS1-RFLP data analyzed by software NTSYS-PC，the similarity coefficient varied from 0.460 0 to 0.800 0，the isolates were clustered into 3 groups at the similarity coefficient of 0.60．No obvious association was found between DNA polymorphism and pathogen races differentiations as identified by biological tests on cucurbitaceae，also no association was found between the genetic diversity and any other of parameter tested：geographic，host origin or greenhouse type.
