Submitted to: Potato Progress
Publication Type: Popular Publication
Publication Acceptance Date: February 15, 2002
Publication Date: March 15, 2002
Citation: BROWN, C.R., GRUNWALD, N.J., LOZOYA-SALDANA, H. BREEDING FOR DURABLE RESISTANCE TO LATE BLIGHT: THE MISSING MEXICAN LINK. POTATO PROGRESS. 2(5):1-3. 2002. Technical Abstract: Late blight, a foliar and tuber disease caused by the water mold Phytophthora infestans, is a highly variable pathogen of potato. Potatoes may be resistant to one form, but completely susceptible to another form that will appear at a later time. For this reason it is necessary to check the durability of resistance to late blight. Screening potato genotypes in the Toluca Valley of Mexico is advantageous because the late blight that occurs there is the most variable in the world. Potatoes with race-specific, non-durable resistance will generally show high susceptibility in the first season of exposure. The USDA/ARS has been screening materials since 1995 in the Toluca Valley in a cooperative research program with the Mexican International Late Blight Research Organization PICTIPAPA. Numerous valuable populations have been characterized and specific clones identified that have resistance. One clone, A90586-11, has been shown to have a moderate level of durable resistance in Toluca. This clone has shown excellent yield and processing quality in the Northwest and may be released as a new late blight resistant variety. The work in Mexico has assured researchers in the US that this clone has true durable resistance.