Mycelial compatibility reactions of Australian 'Fusarium graminearum' and 'F. pseudograminearum' isolates compared with AFLP groupings

Using the mycelial reactions of 435 combinations of 14 'Fusarium pseudograminearum' and 15 'F. graminearum' isolates, it was demonstrated for the first time that mycelial reactions/barrage formation cannot be clearly used to distinguish 'F. graminearum' and 'F. pseudograminearum'. Mutually compatible isolates produced very different patterns of compatibility with other isolates. However, about 60% of pairings between 'F. graminearum' and 'F. pseudograminearum' isolates were compatible, indicating common ancestry. The Mantel tests used to determine any possible associations between mycelial compatibility reactions and AFLP genotypic diversity data revealed no association between the two systems in either species. In addition, no association was found between mycelial compatibility reactions and sexual reproduction in the two species. Implications of the higher frequency of mycelial compatibility reactions observed in 'F. pseudograminearum' than in 'F. graminearum' are discussed.