Exploring Fusarium head blight resistance in a winter triticale germplasm collection

Fusarium head blight (FHB; caused by Fusarium graminearum) is a destructive disease of wheat (Triticum spp.), barley (Hordeum vulgare), rye (Secale cereale L.), and triticale (xTriticosecale Wittmack) not only reducing their yield but also contaminating the grain with mycotoxins such as deoxynivalenol (DON). Developing varieties with genetic resistance is integral to successfully manage FHB. Triticale acreage worldwide is steadily increasing. However, the genetic diversity of triticale for FHB resistance is not well characterized. In the present study, a sequential screening of a set of winter triticale accessions from a global collection was done for their type-2 FHB resistance and DON accumulation. In the first-year screening, 298 triticale accessions were tested for FHB in an artificially inoculated, misted-field nursery with high inoculum density. Most of the triticale accessions were susceptible to FHB, and only 8% of the accessions showed resistance in the field nursery screening. Next, the 24 resistant accessions identified in the nursery screening were tested for 2 years in greenhouse and 17 accessions showed significantly lower FHB severity in Year 2 and/or Year 3. These 17 resistant accessions were further tested for their FHB severity and DON accumulation in Year 4 in greenhouse and for DON accumulation in Year 5 in the field FHB nursery. Eight accessions showed significantly lower FHB severity and nine accessions showed DON accumulation of less than 1 mg/kg in Year 4 greenhouse testing. Eleven accessions had significantly lower DON concentration than the susceptible check in the Year 5 field screening. The resistant accessions common across all years identified in the study can be used for enhancing FHB resistance and reducing DON accumulation in triticale breeding programs. A set of 298 triticale accessions was sequentially tested for FHB severity and DON content over multiple years. Only 2% of the accessions were found to be resistant and with low DON content across all the years. The robustly characterized accessions with low FHB severity and DON content can be used as sources of resistance.