Collecting, characterization, and variability of Phytophthora infestans (Mont.) de Bary, at its centre of origin, Mexico
Since the 1950s, it is widely accepted that the central highlands of Mexico are the centre of origin of the potato and tomato late blight pathogen Phytophthora infestans (Mont.) de Bary, mainly due to the continuous presence of the A1:A2 mating types that generate sexually derived progenies, which coexist in nature with wild Solanum species of the area. It has brought about common international interest because of the genetic plasticity of the oomycete and the epidemic onsets for more than the last twenty years in many potato growing regions of the world. Collecting, conservation, and characterization of P. infestans strains is a continuous concern of the International Cooperative Program on Potato Late Blight (PICTIPAPA) of the Chapingo University, in cooperation with national and international research and education institutions. A wide variability of the oomycete has been consistently observed. For instance, all its pathogenic races are present in the Toluca Valley every year. However, these races are not specifically related to the genotypes isolated from the indicator plants. Races and genotypes are independent concepts. Also, a tendency towards homothallism has been observed in the region for the last ten years. Genotypic profiles of recent collections do not fit in Canadian, North American, or South American classifications. A review of recent reports and the current status of the topic regarding hosts, fungicide-resistance, and isolates from geographical areas within the central highlands of Mexico are discussed.
Lozoya, H., Serrano, R., Maria, I., Santos, A. and Nayeli Robledo, M. 2015. Collecting, characterization, and variability of Phytophthora infestans (Mont.) de Bary, at its centre of origin, Mexico. Acta Hort. (ISHS) 1105:163-168
potatoes, Solanum tuberosum, genetic diversity, late blight