MOLECULAR VARIATION WITHIN SOME JAPANESE ISOLATES OF VERTICILLIUM-DAHLIAE

Eight isolates of Verticillium dahliae from Japan, classified into four groups based on pathogenicity to differential hosts, were compared with isolates in previously defined RFLP groups. Within each of two of the pathogenicity groups (JB and JC) the pairs of haploid isolates were closely related but those in a third group (JA; isolates not pathogenic to sweet pepper or tomato) were not. Only one of the six haploid isolates (one of the two in the JA group) could be placed in an existing RFLP group. The two diploid isolates (the JD pathogenicity group) were similar to RFLP group D and only distantly related to the six haploid isolates. Of the Japanese pathogenicity groups, only JD corresponded to an existing RFLP group.