Deoxynivalenol Content in Common and Durum Wheat Kernels of Old and Modern Cultivars Under Organic Farming

The mycotoxin contamination of flours is an important concern of the organic sector, in which no fungicide can be applied to the crop. The most common toxin occurring in wheat flours is deoxynivalenol (DON) that belongs to the trichothecene class and is produced by several fungi of the Fusarium genus (mainly F. culmorum and F. graminearum). Two different field experimental trials were set up for two subsequent growing seasons (2009/2010; 2010/2011): 1) comparison between 1 modern (Palesio) and 5 old (Inallettabile, Andriolo, Gentil Rosso, Verna, Frassineto) common wheat varieties under organic farming; 2) comparison between one old durum-type (Kamut®Khorasan) and one modern durum wheat variety (Claudio) under organic farming. Different DON accumulation in the grains was observed comparing the two cropping years as a result of changing weather conditions: wheat varieties grown during the first cropping season presented higher mycotoxin levels (0.19 and 1.19 mg/kg for common and durum wheat, respectively) as compared to those observed in the second year (0.02 and 0.33 mg/kg for common and durum wheat, respectively). The higher DON levels of Kamut and Claudio flours confirmed the higher susceptibility of durum-type wheat to Fusarium head blight, but no differences were observed among genotypes for each wheat species. Interestingly, despite of the interdiction in using fungicides, in common wheat cultivars grown according to organic farming the mycotoxin content was lower than the legislative limits set for all the food categories, as indicated in the current EU regulation (EC N. 1126/2007).