Morphological characterization of wild populations of Solanum lycopersicum var. cerasiforme in the tomato domestication area

Abstract

Wild tomatoes Solanum lycopersicum var. cerasiforme are found in regions with wide environmental diversity, in the state of Veracruz, México, which has originated morphological variations within this group leading to his adaptation to different environments. The aim of this study was to investigate the morphological variations of S. l. var. cerasiforme in his domestication area. We collected plants and fruits during the field trips, and we extracted seeds from these fruits to sow them later, under the greenhouse. We evaluated 35 characters according to the IPGRI (International Plant Genetic Resources Institute) descriptors in 10 collections of S. l. var. cerasiforme, we used a completely random design. In order to compare de collections and analyze the variables we performed variance analysis, principal component analysis and cluster analysis with euclidean distance (UPGMA clustering method). We found significant differences between the variables (Tukey, P≤ 0.05), except for the style length and flower number per plant variables. We found that 91 % of the collections have a pistil inserted and 9 % exert. The first two components explained 78 % of the total variation. The dispersion of the collections in the four quadrants of the first two components indicated great phenotypic diversity. We found four groups and we observed the greatest variation in the yield and reproductive variables. This study shows intraspecific morphological differences between wild tomato populations in the state of Veracruz, a state with a wide environmental and ecosystem diversity. It can be said that in terms of morphological characterization of wild tomato species and cultivated tomatoes for both the pattern of variability is the same. The populations we have studied could constitute a valuable germplasm bank for genetic improvement programs.