Field Screening of Solanum demissum Confirms its late Blight Resistance in the Toluca Valley, Mexico

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 to reconfirm 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.