Mycotoxin production of 31 Fusarium graminearum isolates and aggressiveness against wheat seedlings

31 Fusarium graminearum isolates were tested to determine the extent of their in vitro mycotoxin production and their aggressiveness and the results from both tests were correlated. Rice samples inoculated with the different F. graminearum isolates were analysed for the trichothecene mycotoxins deoxynivalenol (DON), acetyl-deoxynivalenol (ADON; 3- and 15-acetyl-DON together), nivalenol (NIV) and acetyl-nivalenol (ANIV) using reversed-phase HPLC. The aggressiveness test was carried out on wheat seedlings inoculated with F graminearum at the sprout base. DON and ADON were produced by all F graminearum isolates; neither NIV nor ANIV were identified in any. The toxin amounts varied substantially, e. g. from 0.1 to 812 mg kg(-1) for DON. DON and ADON production correlated closely. A high variability was also shown regarding the extent of aggressiveness whereby the necrotic area on the sprout base varied vertically from 5.8 to 22.0 mm. The data on toxin production and on the aggressiveness of the 31 isolates tested showed no correlation whether or not the toxins were applied individually or as a total.