Intermediate Wheatgrass TLI breeding C07, C10 Disease Evaluation and GWAS

Intermediate wheatgrass (IWG) [Thiniopyrum intermedium (Host) Barkworth & D. R. Dewey] is a promising perennial grain candidate that The Land Institute has been directly domesticating since 2001. Grain from improved IWG can be sold under the trademark Kernza. Resistance to Fusarium head blight (FHB) is a high priority trait to reduce toxin content of the grain and protect the value and seed supply of Kernza. We evaluated two breeding cycles of IWG from 2018-2022 with each cycle containing ~500 unique genets to evaluate disease response and identify chromosomal regions associated with disease resistance. Quantitative trait loci (QTL) were mapped for 19 different traits using 32,067 markers in 21 linkage groups with genome-wide association analysis. A total of 210 unique marker-trait associations (MTA) were detected across 15 different traits with five of these traits related to Fusarium head blight (FHB) resistance. We additionally used the BLAST Alignment Creation tool to identify homologies between the Fhb1 region of wheat and the IWG genome, including an IWG GDSL-like lipase/Acylhydrolase gene (Thintv31194873.m.g) with similarity (query = 89%) to the T. aestivum Sumai 3 Fhb1 genomic sequence. Other candidate genes outside of the Fhb1 region were identified for Fusarium resistance with functions associated with toxin reduction and defense hormones and metabolites. These results provide loci that can be used to develop genetic markers for selection through breeding to improve IWG’s genetic resistance to FHB.