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The "bell pepper" or "chino criollo" tomato is a native Mexican variety with similar characteristics to the "Saladette" tomato and the potential to be used as a source of germplasm to generate commercial hybrids of this type. The aim of this investigation was to identify and select advanced lines with a wide genetic base, derived from crosses between Saladette tomatoes and native populations to generate free pollination varieties and potential parents of Saladette tomato hybrids. The hypothesis was that crosses between native populations and Saladette commercial hybrids generate outstanding offspring. The 103 genotypes evaluated included 10 native parents, three parents derived from commercial hybrids, one commercial hybrid control ("El Cid") and 89 S4 advanced lines. The evaluation was carried out in a greenhouse and hydroponics during the 2020 spring-summer cycle, using a randomized complete block experimental design with three replications and four plants per replication. The total weight and number of fruits were recorded based on the sum of the two cuts performed. The days to flowering of the first cluster, average fruit weight, and total soluble solids were also determined. Analyses of variance were carried out for each variable, as well as orthogonal contrasts and correlations between different combinations of the materials of interest. The comparison of means was carried out using Tukey's test (p £ 0.05). Nine advanced lines with similar or greater characteristics to the control were identified and are recommended to be recombined genetically in a diallelic cross scheme to identify new outstanding offspring. The advanced line 2051 (LOR85 X C) was identified, with a similar yield to that reported for the control, which can be used as an open pollination variety since it has similar characteristics to the control "El Cid", but with native tomato genes. [ABSTRACT FROM AUTHOR]

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Tomato’s (Solanum lycopersicum L.) narrow genetic background limits its genetic improvement. The tomato genetic base may be broaden with the use of its native and wild populations as they are a source of useful alleles, to increase yield, quality, and resistance to biotic and abiotic factors that cause stress. Native tomato collections from Mexico have a greater genetic diversity than that of elite germplasm; this implies that genotypes with agronomic, morphological and allelic characteristics different from such elite germplasm may be selected. Therefore, our objective was to evaluate the genetic diversity of 26 accessions of native Mexican tomatoes and identify the best ones for their use in tomato breeding. An agromorphological characterization with 20 traits in a completely randomized experimental design with three replications was performed along with a study with molecular SSR markers. The principal components analysis and hierarchical grouping allowed to identifying four groups with outstanding yield, size and internal fruit quality characteristics. The molecular markers were used to calculate the Shannon index, Nei index and Roger genetic distance, from which they generated seven groups, whose inbreeding and fixation coefficients were close to 1. This indicated the presence of inbreeding and wide differences within of the identified groups. With both characterizations and the Gower distance, the separation of S. lycopersicum L. and S. pimpinellifolium L. species was determined. The native Mexican tomato genotypes possess great genetic diversity and allelic variability that would allow their use in different breeding programs to incorporate alleles for yield and yield components, size and sugars content in the cultivated tomatoes. [ABSTRACT FROM AUTHOR]