A COMPARISON OF BIOLOGICAL, MOLECULAR AND ENZYMATIC MARKERS TO INVESTIGATE VARIABILITY WITHIN MICRODOCHIUM-NIVALE (FRIES) SAMUELS AND HALLETT

The variation among isolates of Microdochium nivale obtained from a range of hosts and locations in Europe was investigated on the basis of conidial morphology, restriction fragment length polymorphisms (RFLPs) of the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA), esterase profiles, aggressiveness on wheat seedlings and perithecial production. One homogeneous group was resolved on the basis of esterase profiles and RFLPs of the ITS region of rDNA. The isolates within this group possessed ITS profiles identical to reference isolates of var majus from other workers and therefore were assigned to var majus. The isolates within this homogeneous var majus grouping were obtained from a range of locations throughout Europe, demonstrating that it is not restricted to the United Kingdom. Nineteen esterase profiles and 2 ITS profiles were detected among the remaining isolates, suggesting that this grouping may be comprised of further sub-groups. The results demonstrated that several isolate types may exist at a single location and that pathogenicity to wheat seedlings was not related to any of the traits analysed.