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SPECIAL SESSION: I. E. Melhus Graduate Student Symposium: Harnessing Host Resistance to Strengthen Management Strategies Amidst Global Threats

Identifying Candidate Genes associated with Gray Leaf Spot and Crown Rust Resistance in Tall Fescue using GWAS

Tuesday, August 5, 2025
4:00 PM - 4:40 PM HST
Location: Room 311
Gray leaf spot (GLS), caused by Magnaporthe oryzae, and crown rust (CR), caused by Puccinia coronata, are significant fungal diseases of tall fescue (Festuca arundinacea), a widely cultivated cool-season turf and forage grass in the U.S. While breeding efforts have traditionally prioritized turf quality and forage yield, the growing impact of these diseases makes resistance a critical target for breeding. To identify loci contributing to disease resistance in tall fescue, we conducted a genome-wide association study (GWAS) on 283 accessions grown across three locations in Georgia during the 2023 and 2024 seasons. Notable genotype-by-environment interactions were observed.. Using the tGBS technique, we identified 155,530 SNP markers, which led to the discovery of three marker-trait associations (MTAs) for GLS resistance on chromosomes 4G1, 6G1, and 2G2, and seven MTAs linked to CR resistance on chromosomes 6G1, 7G1, 4G2, 3P, and 5P. With Chinese Spring wheat (Triticum aestivum, IWGSC RefSeq v2.1) as the reference genome, candidate genes playing roles in pathogen recognition and defense responses, including genes encoding leucine-rich repeats, protein kinases, and F-box proteins, were identified. These candidate genes could be valuable for future breeding programs aimed at enhancing disease resistance in tall fescue.