Morphological diversity of native to Central and Southern Mexico tomato fruits

Abstract

Mexico, recognized as a center of domestication and diversification of the tomato (Solanum lycopersicum L.). Native populations distributed throughout the central and southern regions of the country represent an invaluable source of alleles for the genetic improvement of the species. Therefore, characterizing these populations is fundamental for identifying traits of agronomic interest for developing varieties or hybrids. This study aimed to morphologically characterize the fruit of lines generated in the tomato breeding program of the National Institute of Forestry, Agricultural and Livestock Research (INIFAP). Sixteen tomato lines were cultivated under greenhouse conditions during the 2022-2023 fall-winter cycle, using a randomized complete block design with four replications. Twenty-two morphological traits of the fruit were evaluated based on UPOV and IPGRI descriptors, and cluster and correspondence analyses were performed. Of the traits evaluated, 17 showed significant variability, notably green stripes, epidermal gloss, intensity of green color on the shoulder, size of the green shoulder, and intensity of green color excluding the shoulder. Five fruit shapes were distinguished: cherry, kidney, half-kidney, saladette, and creole chinese, distributed across different states of the country. Cluster analysis revealed two main germplasm groups, suggesting distinct sources of genetic diversity. The results highlight the importance of morphological traits for genetic improvement of the tomato, enabling the selection of outstanding lines with potential for the development of gourmet materials and open-pollinated varieties.