Selection of potato genotypes Solanum tuberosum group Andigena by their tolerance to Phytophthora infestans (Mont.) of Bary.

Phytophthora infestans is the most limiting biotic problem of potato crop in Colombia and the world. It is a pathogen that threatens the sustainability of the crop. Therefore, it is necessary to evaluate work collections of potato to identify genotypes that show disease tolerance. The objective of this work was to select genotypes of Solanum tuberosum group Andigena by their tolerance to P. infestans. This study was carried out under conditions of Pasto, in the South of Colombia at 2,820 masl. A total of 76 introductions of guata potatoes were evaluated under natural inoculum, including Capiro as a susceptible control, Betina as moderately tolerant and Pastusa Suprema as highly tolerant. The number of stems and stolons per plant was registered. Disease severity assessments and traits related to the area under the disease progress curve were made. At harvest stage, yield values per plant and its components were recorded. Principal Component and Classification analyses discriminated tolerant introductions of susceptible. Significant positive correlations were found between the yield with the number of stolons, tubers per plant and tuber weight, and negative correlations with severity and area under the relative disease progress curve. The selected introductions showed high yield per plant and mostly minor severities to the population, indicating an agronomic potential that must be evaluated in different environments to determine its adaptability and stability. UdenarStGua53, UdenarStGua61, UdenarStGua68, UdenarStGua73, UdenarStGua75, UdenarStGua77 y UdenarStGua78, coming from the International Potato Center (CIP) are confirmed as a source of tolerance to P. infestans and can be considered as parental within species improvement programs. [ABSTRACT FROM AUTHOR]