Field screening of Solanum demissum confirms its late blight resistance in the Toluca Valley, Mexico

Authors: DÍAZ-GARCÍA, GABRIELA - University Of Chapingo; ENCISO-MALDONADO, GUILLERMO ANDRE - University Of Chapingo; DIAZ-GARCIA, LUIS - University Of Chapingo; LEGARIA-SOLANO, JUAN PORFIRIO - University Of Chapingo; Bamberg, John; LOZOYA-SALDANA, HECTOR - University Of Chapingo

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2024
Publication Date: 3/12/2024
Citation: Díaz-García, G., Enciso-Maldonado, G., Diaz-Garcia, L., Legaria-Solano, J., Bamberg, J.B., Lozoya-Saldana, H. 2024. Field screening of Solanum demissum confirms its late blight resistance in the Toluca Valley, Mexico. American Journal of Potato Research. 1-10 (2024). https://doi.org/10.1007/s12230-024-09945-7.
DOI: https://doi.org/10.1007/s12230-024-09945-7

Interpretive Summary: Potato is most eaten vegetable crop in the world, but needs constant improvement. The most damaging fungal disease is late blight. We surveyed the resistance of 94 breeding stocks from the US Potato Genebank. These were a wild related potato species, Solanum demissum. The tests were done in Mexico, the presumed origin site of late blight and where disease pressure is most severe. Nearly 90% were highly resistant. Identifying these most resistant stocks now allows their deliberate selection for use in breeding. This wild potato species is easily crossed with cultivated potato. The payoff will be more efficient production of higher-quality potatoes, improving food security, and allowing reduction of pesticide applications that may impact the health of people and the environment.

Technical Abstract: Late blight is a major threat to potato crops worldwide. Despite the host’s genetic improvements, continuous evolution of the pathogen and climate change makes it necessary reconfirmation of genetic resistance sources. Solanum demissum has long been identified as a valuable source of late blight resistance genes. The aim of this study was to reevaluate S. demissum accessions for late blight resistance under natural infection in the Toluca Valley, México. Most of the accessions exhibited resistance, with minor variations between two consecutive growing seasons. Eighty three out of 94 accessions that were evaluated in both years were resistant, thirty-three accessions that were exposed to the pathogen for only one season were also resistant. However, a response variation was observed in some accessions. This research characterizes and reconfirms the resistance of S. demissum, providing information for breeding programs and optimizing the use of these genetic resources.