A Genome Wide Association Study for Fusarium Head Blight Resistance in Southern Soft Red Winter Wheat.

Fusarium head blight (FHB) is a disease of small grains caused by the fungal pathogen Fusarium graminearum. FHB poses potential economic losses and health risks due to the accumulation of the mycotoxin deoxynivalenol (DON) on infected seed heads. The objectives of this study are: 1) evaluate soft red winter wheat (SRWW) lines for resistance to FHB in terms of resistance to initial inoculum (incidence); resistance to spread within the head (severity); resistance to DON accumulation; and resistance to Fusarium damaged kernels (FDK), 2) determine the frequency and effect of known FHB resistance genes and quantitative trait loci (QTL), and 3) identify novel resistance loci using a genome wide association (GWA) approach. In 2016-2017, 360 SRWW breeding lines were evaluated in inoculated misted FHB nurseries in Fayetteville and Newport, AR and Winnsboro, LA in a randomized complete block design. At all locations, lines were sown in two row plots, inoculated with F. graminearum infected corn (Zea mays L.) and overhead misted throughout the months of April and May to provide optimal conditions for FHB infection. In addition to visual ratings and DON analysis, lines are currently being screened with KASP® markers linked to known FHB resistance genes, including Fhb1, 3BSc from Massey and recently identified QTL for native resistance from Jamestown (1B, 6A) and Bess (2B, 3B). SNP markers generated through genotype by sequencing will be used to perform GWA in order to identify marker-trait associations for FHB resistance. Results from this study will facilitate the development of SRWW cultivars with improved resistance to FHB. The latest results will be presented.