Genome-Wide Association Mapping of Resistance QTL to Fusarium Head Blight in Spring Wheat Lines Grown in Pacific Northwest and CIMMYT.

Fusarium head blight is one of the destructive diseases of wheat in humid and semi-humid areas of the world. It has emerged in the Pacific Northwest (PNW) in recent years because of changing climate and rotation practice. The objectives of the present study were to characterize FHB resistance in spring wheat lines grown in PNW and CIMMYT and identify QTL associated with FHB resistance. A total of 170 spring wheat lines were evaluated in greenhouse and in field at Aberdeen, ID as well as at St. Paul and Crookston, Minnesota in 2015 and 2016. Based on two years’ data in greenhouse and field, 18 lines showed disease severity less than 25% in five out of seven environments. These lines have no Sumai 3 or related backgrounds and can be the starting resources to develop FHB resistant cultivars for the PNW areas. The 170 lines were genotyped using high-density Illumina 90K single nucleotide polymorphisms (SNPs) assay and some SSR markers. A genome-wide association analysis was conducted with mixed model (Q+K) using the phenotyping data and the genotyping data. Consistent significant SNP-trait associations detected in three or more environments were found on chromosomes 1A, 1B, 2A, 2B, 6A, 6B, 7A, and 7B. The SNPs on chromosome 3B and the SSR marker umn10 were not significantly detected, indicating the Fhb1 is not the major locus conferring FHB resistance in this panel. In summary, the resistance resources and associated SNP markers detected in this study can be used in the development of new FHB resistant cultivars in the PNW areas.