Genome-Wide Association Mapping of Fusarium Head Blight Resistance in Spring Wheat Lines Developed in the Pacific Northwest and CIMMYT.

Fusarium head blight (FHB) is a destructive disease of wheat in humid and semihumid areas of the world. It has emerged in the Pacific Northwest (PNW) in recent years because of changing climate and crop rotation practices. Our objectives in the present study were to identify and characterize quantitative trait loci (QTL) associated with FHB resistance in spring wheat lines developed in the PNW and the International Maize and Wheat Improvement Center. In total, 170 spring wheat lines were evaluated in field and greenhouse trials in 2015 and 2016. Fourteen lines showing consistent resistance in multiple environments were identified. These lines are valuable resources in wheat variety improvement of FHB resistance because they have no Sumai 3 or Sumai 3-related background. The 170 lines were genotyped using a high-density Illumina 90K single-nucleotide polymorphisms (SNP) assay and 10 other non-SNP markers. A genome-wide association analysis was conducted with a mixed model (Q+K). Consistent, significant SNP associations with multiple traits were found on chromosomes 1B, 2B, 4B, 5A, 5B, and 6A. The locus on chromosome 5B for reduced deoxynivalenol content may be novel. The identified QTL are being validated in additional mapping studies and the identified resistant lines are being used in variety development for FHB resistance and facilitated by marker-assisted selection.