Relationship between Fusarium Head Blight, Kernel Damage, Concentration of Fusarium Biomass, and Fusarium Toxins in Grain of Winter Wheat Inoculated with Fusarium culmorum.

Winter wheat lines were evaluated for their reaction to Fusarium head blight (FHB) after inoculation with Fusarium culmorum in two field experiments. A mixture of two F. culmorum chemotypes was applied (3ADON-deoxynivalenol producing, NIV-nivalenol producing). Different types of resistance were evaluated, including head infection, kernel damage, Fusarium biomass content and trichothecenes B (deoxynivalenol (DON), and nivalenol (NIV)) accumulation in grain. The aim of the study was to find relationships between different types of resistance. Head infection (FHB index) and Fusarium damaged kernels (FDK) were visually scored. Fusarium biomass was analysed using real-time PCR. Trichothecenes B accumulation was analysed using gas chromatography. Wheat lines differ in their reaction to inoculation for all parameters describing FHB resistance. We found a wide variability of FHB indexes, FDK, and Fusarium biomass content. Both toxins were present. DON content was about 60% higher than NIV and variability of this proportion between lines was observed. Significant correlation was found between head infection symptoms and FDK. Head infection was correlated with F. culmorum biomass and NIV concentration in grain. No correlation was found between the FHB index and DON concentration. Similarly, FDK was not correlated with DON content, but it was with NIV content; however, the coefficients were higher than for the FHB index. Fusarium biomass amount was positively correlated with both toxins as well as with the FHB index and FDK. Environmental conditions significantly influenced the DON/NIV ratio in grain. In locations where less F. culmorum biomass was detected, the DON amount was higher than NIV, while in locations where more F. culmorum biomass was observed, NIV prevailed over DON.