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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #374295
Research Project: Maximizing the Impact of Potato Genebank Resources: Development and Evaluation of a Wild Species Genotype Diversity Panel

Location: Vegetable Crops Research

Title: Screening of wild potatoes identifies new sources of late blight resistance

Author
item Karki, Hari
item Jansky, Shelley
item Halterman, Dennis

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2020
Publication Date: 8/5/2020
Citation: Karki, H.S., Jansky, S.H., Halterman, D.A. 2020. Screening of wild potatoes identifies new sources of late blight resistance. American Journal of Potato Research. https://doi.org/10.1094/PDIS-06-20-1367-RE.
DOI: https://doi.org/10.1094/PDIS-06-20-1367-RE

Interpretive Summary: Potato late blight is a continual problem for potato production worldwide. While most cultivated potato varieties are susceptible to the disease, wild relatives of potato are an excellent source of resistance. In order to incorporate resistance into new potato varieties, ideal sources of resistance (single gene resistance, sexual compatibility with cultivated potato) must first be identified. We screened 386 accessions of 67 different wild potato species available from the U.S. Potato Genebank against the late blight pathogen Phytophthora infestans in a detached leaf assay. From this screen, we identified 40 accessions with strong disease resistance. We found several species that were never before reported to be resistant to late blight. These new species could be a novel source of late blight resistance.

Technical Abstract: Late blight of potato is considered to be one of the most devastating plant diseases in the world. Most cultivated potatoes are susceptible to this disease. However, wild relatives of potatoes are excellent sources of late blight resistance. We screened 386 accessions of 67 different wild potato species available from the U.S. Potato GenBank against the late blight pathogen Phytophthora infestans in a detached leaf assay (DLA). Although all plants in 268 accessions (69%) were susceptible, in 40 accessions (10%) all screened plants were resistant. Both resistant and susceptible plants were found in 37 accessions (10%) and in 2 accessions, all tested plants showed a partial resistance phenotype. The remaining 27 accessions showed segregation of resistance, partial resistance and susceptible individuals. We found several species that were never before reported to be resistant to late blight. These new species could be a novel source of late blight resistance. P. infestans strain-specific screening of some of the selected species was conducted to identify the presence of the RB resistance gene. We found some LB resistant accessions in S. verrucosum, S. stoloniferum and S. morelliforme are susceptible to the RB overcoming isolate NL13016 indicating the presence of the RB gene.