Genome-wide association study of Fusarium head blight resistance in wheat accessions from Plant Gene Resources of Canada using 90K and 40K SNP arrays

Fusarium head blight (FHB), caused by Fusarium species, is a major threat to global wheat production, reducing yield and quality and contaminating grain with harmful mycotoxins. This study utilized a genome-wide association study to investigate FHB resistance in a diverse collection of 300 hexaploid wheat (T. aestivum L.) pure lines selected for their FHB resistance from 4,000 Triticum accessions obtained from Plant Gene Resources of Canada (PGRC). Phenotypic data were collected across multiple site-years (2019-2024) and the accessions were genotyped by high-density SNP arrays (40K and 90K). One hundred eighty-two quantitative trait nucleotides (QTN) associated with FHB resistance traits were identified across all chromosomes except 6D. Among these, 30 QTN consistently detected across multiple site-years were clustered into 13 QTL, with six prioritized for breeding applications due to their significant contributions to resistance. Novel loci such as QFhb.usask-3B.1was identified, harboring potential candidate genes encoding transcription factors and resistance proteins involved in biotic stress responses. Eight most resistant PGRC lines were identified based on Best Linear Unbiased Predictors analysis, representing diverse regions and carrying these identified QTL. This study advances the understanding of FHB resistance mechanisms and provides genomic resources for breeding programs aimed at developing improved wheat cultivars with enhanced resistance.