Distribution and Climatic Adaptation of Wild Tomato (Solanum lycopersicum L.) Populations in Mexico

Abstract

Tomato (Solanum lycopersicum L.) is a vegetable with worldwide importance. Its wild or close related species are reservoirs of genes with potential use for the generation of varieties tolerantor resistant to specific biotic and abiotic factors. The objective was to determine the geographicdistribution, ecological descriptors, and patterns of diversity and adaptation of 1296 accessions ofnative tomato from Mexico. An environmental information system was created with 21 climaticvariables with a 1 km2 spatial resolution. Using multivariate techniques (Principal ComponentAnalysis, PCA; Cluster Analysis, CA) and Geographic Information Systems (GIS), the most relevantvariables for accession distribution were identified, as well as the groups formed according to theenvironmental similarity among these. PCA determined that with the first three PCs (PrincipalComponents), it is possible to explain 84.1% of the total variation. The most relevant informationcorresponded to seasonal variables of temperature and precipitation. CA revealed five statisticallysignificant clusters. Ecological descriptors were determined and described by classifying accessions in Physiographic Provinces. Temperate climates were the most frequent among tomato accessions. Finally, the potential distribution was determined with the Maxent model with 10 replicates by crossvalidation, identifying areas with a high probability of tomato presence. These results constitute a reliable source of useful information for planning accession sites collection and identifying accessions that are vulnerable or susceptible to conservation programs.