Factors of wheat grain resistance to Fusarium head blight

Fusarium head blight (FHB), caused by Fusarium graminearum, is an important wheat disease that affects grain yield and conformation, and contaminates grains with mycotoxins, including the trichothecene deoxynivalenol (DON). The impacts of Fusarium infections on grain filling, grain deformation and rheological properties were assessed under different environmental conditions. Genotypes with elevated grain anthocyanin content were used. Resistance of seven wheat varieties and breeding lines was assessed with artificial infections in the field. Grains from infected and control plots were assessed for proportion of Fusarium damaged kernels, grain filling (thousand kernel weight) and DON accumulation. Biochemical and rheological properties of harvested grain were also assessed. Grain resistance to Fusarium has several components, including resistance against DON accumulation, deformation and stability of grain filling. These mechanisms are interdependent but act independently. Resistance against DON contamination was highly influenced by environmental conditions, but environment had little effect on the other resistance components. Anthocyanins and protein concentrations were unchanged in infected grains, suggesting that FHB does not affect grain biosynthesis processes but impacts the transport of assimilates caused by changes in grain composition. We suggest that this is the reason for the alterations of rheological properties. The greater the grain resistance, the less was the impact on dough properties. This study suggests that the resilience of rheological properties under FHB infection pressure is an additional component of grain resistance to the disease.