Genetics of Fusarium head blight resistance in soft red winter wheat using a genome-wide association study

Authors: GHIMIRE, B - University Of Georgia; MERGOUM, M - University Of Georgia; MARTINEZ-ESPINOZA, A - University Of Georgia; Sapkota, Suraj; PRADHAN, S - University Of Florida; BABAR, M - University Of Florida; Bai, Guihua; DONG, Y - University Of Minnesota; BUCK, J - University Of Georgia

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2022
Publication Date: 5/31/2022
Citation: Ghimire, B., Mergoum, M., Martinez-Espinoza, A.D., Sapkota, S., Pradhan, S., Babar, M.A., Bai, G., Dong, Y., Buck, J.W. 2022. Genetics of Fusarium head blight resistance in soft red winter wheat using a genome-wide association study. The Plant Genome. e20222. https://doi.org/10.1002/tpg2.20222.
DOI: https://doi.org/10.1002/tpg2.20222

Interpretive Summary: Fusarium head blight (FHB) is one of the most destructive fungal wheat (Triticum aestivum L.) disease. FHB first emerged in the US and UK around 1884 and caused major epidemics in the 1990s in the US Midwest and Canada causing multi-billions in yield losses. Deploying host plant resistance is a sustainable, cost-effective, and environmentally friendly approach to FHB management. Therefore, the objective of the present study was to characterize FHB resistance in a panel of 236 soft red winter wheat lines across greenhouse and field environments and to explore the novel genomic loci associated with different FHB resistance. Genome-wide association studies (GWAS) conducted using phenotypic data from field and greenhouse screening and >27K SNPs data discovered 171 significant marker-trait association for FHB traits and plant height. Of these, 11 QTL were major effect explaining >10% phenotypic variation, three were stable across multiple environments, and five exhibited a pleiotropic effect. Genomic loci detected for FHB resistance in this study could potentially help breeding programs to successfully introgress resistance loci into elite wheat lines for FHB resistance improvement.

Technical Abstract: Host resistance is the most effective and sustainable approach to manage the negative impact of Fusarium head blight (FHB) on wheat (Triticum aestivum L.) grain yield and quality associated with harmful mycotoxins. The objective of this study was to characterize the phenotypic response and identify quantitative trait locus (QTL) conditioning different FHB resistance types using a panel of 236 elite soft red winter wheat lines in a genome-wide association study. The panel was phenotyped for five FHB and three morphological traits under two field and two greenhouse environments in 2018-19 and 2019-20. We identified 160 significant marker-trait associations (MTAs) related with FHB traits and 11 MTAs for plant height. Pairwise linkage disequilibrium resolved eleven major effect QTLs that surpassed the Bonferroni correction threshold of -log10(P) > 5.74 and explained more than 10% phenotypic variation. Among these major loci, three QTLs were consistently identified in multiple environments and were considered stable, while five QTLs exhibited a pleiotropic effect collectively located on chromosomes 1BL, 3BL, 5BL, 7AS, and 7AL. A comparison study with previously mapped loci indicates that QTLs QFhb-3BL, QFhb-5AS, QFhb-5BL, QFhb-7AS.1, QFhb-7AS.2, and QFhb-7BS are probably novel and need further investigations. Pyramiding multiple resistance alleles from all major effect QTLs resulted in a significant reduction of FHB incidence, severity, index, deoxynivalenol (DON), and Fusarium-damaged kernel by 17, 43, 45, 55, and 25%, respectively. Further validation of these mapped QTLs from our study could potentially help breeding programs to successfully introgress these resistance loci in elite wheat lines for improved FHB resistance