Assessment of Wild Solanum Species for Resistance to Phytophthora infestans (Mont.) de Bary in the Toluca Valley, Mexico

Ninety-seven accessions of 14 wild Solanum species were evaluated for late blight resistance under natural infection conditions in the Toluca Valley, México, for two consecutive growing seasons. Significant effects were detected for the interaction of Accession/Year variation in Disease Maximum, sAUDPC (standardized AUDPC), r (rate of disease increase per unit time), and T 50 (time to reach 50% of the disease). Continuous variation in Disease Maximum, sAUDPCs, r , and T 50 indicated the presence of unique or multiple strong R genes for disease resistance. Eleven accessions from seven species with a high degree of resistance (R) were identified. Seven accessions from six species were also moderately resistant (MR) in both years. Five accessions of three species were MR or R in just one year, with 23 accessions being of interest as potential sources of resistance . Solanum genotypes that have a wide range of resistance could be used in breeding programs and for molecular genetic studies.