Characterizing resistance to powdery scab

Wednesday, July 30, 2025

9:45 AM - 10:00 AM CDT

Location: Ballroom AB

Presenting Author(s)

AT

Asunta L. Thompson

Associate Professor
North Dakota State University
Fargo, North Dakota

Author(s)

JP

Julie S. Pasche, n/a

Associate Professor
North Dakota State University
Fargo, North Dakota
LS

Laura M. Shannon

Associate Professor
University of Minnesota
St. Paul, Minnesota
SC

Sapphire Coronejo

Ph.D. Student
University of Minnesota
St. Paul, Minnesota

Powdery scab has become increasingly important in North American potato production regions. Root galling and erumpent lesions on tubers are characteristic of the disease caused by the soil-borne plasmodiophorid Spongospora subterranea f. sp. subterranea (Sss). Additionally, this pathogen vectors potato mop top virus (PMTV). Symptoms of both diseases can render tubers unmarketable and lead to the abandonment of fields for production. Field screening trials were conducted in 2023 and 2024 to determine mean powdery scab severity for more than 200 genotypes across market types. Following RenSeq analysis of foliar tissue for R-gene genotypes, genome wide association mapping using 21,126 SNPs identified significant QTL associated with resistance. Significant hits on chromosomes 6, 11 and 12 suggest potential candidate markers for powdery scab resistance, enriching breeding opportunities and strategies for resistance to Sss.