Comparison of Fusarium Culmorum Isolates Associated with Virulence on Wheat

Fusarium culmorum is one of the most important causal agents of Fusarium head blight (FHB), results in yield and quality reductions and mycotoxin accumulation. It predominates on cereals in North-West of Turkey in cereal growing fields. In this research the aggressiveness among the F. culmorum isolates and reduction on yield was evaluated. Two wheat varieties (Golia and Ceyhan) and 16 isolates of the fungus were enclosed in the research. In addition, the mycotoxin content of zearalenone (ZEA) in the infected kernels was also compared. The wheat heads were inoculated by a syringe at mid-anthesis. Head blight severity was assessed 3 times and the data was used to calculate the area under disease progress curve (AUDPC). Significant variation in aggressiveness of isolates of F. culmorum was observed in both wheat varieties tested. The isolates of F. culmorum reduced significantly thousand kernel weights (TKW) at different levels in both varieties. No interaction was found between ZEA accumulation and isolates or wheat varieties. There was a positive correlation between head weight and TKW, but negative correlation between AUDPC and head weight or TKW. No correlation was found between ZEA and any other parameters assessed. We conclude that the enclosed isolates of F. culmorum differed in aggressiveness and reduced yield at different levels; ZEA accumulation was, however, not correlated with the disease severity. This result suggests that ZEA is not required for pathogenicity; therefore, selection in wheat for reduced visible disease symptoms does not reduce the risk of ZEA contamination.