VARIABILITY AMONGST STRAINS OF FUSARIUM-POAE ASSESSED BY VEGETATIVE COMPATIBILITY AND RAPD POLYMORPHISM

Vegetative compatibility tests and random amplification of polymorphic DNA (RAPD) were used to assess genetic relationships amongst 54 strai ns of Fusarium poae obtained from various geographical regions. Twenty -seven strains were assigned to eight multiple member vegetative compa tibility groups (VCGs), while the other 27 isolates were found to form single-member VCGs. There was a partial correlation between VCG and g eographical origin, but the relationship was not always clear. However , no correlation was observed between the VCG and the host plant of or igin. RAPD patterns were closely associated with VCGs in all cases. Me mbers of VCGs that were interconnected by bridging isolates formed com mon branches in the phenogram constructed on the basis of the RAPD pat terns, while strains that belonged to single-member VCGs were scattere d throughout the phenogram. These data demonstrate that the combinatio n of traditional and molecular methodologies allows reliable intraspec ific subdivisions in an asexual fungus, which is a secondary invader o f a wide range of host plants, and so has never been subject to the in tense selection pressure of a single host species and lacks pathogenic subgroups.