Fusarium head blight (FHB) is an emerging disease of small grains in the Pacific Northwest driven by increased use of pivot irrigation, expansion of corn acreage, and the growing prevalence of Fusarium graminearum. The use of resistant varieties reduces both FHB and deoxynivalenol (DON) contamination in grain. However, most wheat varieties grown in the region are susceptible to FHB, resulting in high levels of DON accumulation. To support the adoption of resistant varieties and reduce FHB pressure, screening nurseries were established at Aberdeen, ID over six growing seasons (2017-2022). These nurseries contained widely grown wheat varieties and breeding lines. Corn spawn inoculum derived from F. graminearum isolates collected from Idaho was applied three weeks before anthesis of most varieties. FHB incidence and disease severity were evaluated at soft dough while FHB index was calculated from disease incidence and severity values. DON concentration was determined from harvested grain samples. On average, across multiple years, 15.9% of the varieties showed moderate resistance to both FHB and DON accumulation. This included five hard red spring, one hard white spring and eight soft white spring wheat varieties. None of the varieties had DON content below the 1-ppm threshold level for human consumption, however, 17 varieties (11.5%) had DON content below the 5-ppm threshold level acceptable for animal feed. Varieties selected in this study with low disease severity and DON accumulation may be used as sources of resistance to improve resistance to FHB in their respective market classes.
Yimer et al. (Thu,) studied this question.