Genetic dissimilarity and phenology of tomato plants based on physical and morpho-agronomic descriptors

Abstract This work was carried out between February and July 2023, to characterize the genetic dissimilarity of tomato accessions from BAGs, using physical and morpho-agronomic characters. Eleven accessions from the Federal University of Viçosa (UFV) BAG, four accessions from the Embrapa Hortaliças BAG and the San Marzano tomato as a control were evaluated. A total of 33 qualitative and nine quantitative descriptors were used. The results show that there is genetic dissimilarity between the accessions evaluated. The physical and quantitative morpho-agronomic characters that contribute the most to genetic dissimilarity are the mass of 10 fruits and the fruit width. The most similar accessions according to the quantitative variables are BGH-6909 and BGH-6908, while the most genetically distant are CNPH-1120 and BGH-6895. The least genetically similar accessions, according to the qualitative variables, are BGH-6899 and CNPH-1120, while the most similar are BGH-6899 and BGH-6976. Significance of Study What is already known on this topic? Previous studies have shown that tomato ( Solanum lycopersicum L.) exhibits wide morphological and agronomic variability; however, much of the genetic potential stored in active germplasm banks (AGBs) has not been properly characterized. Physical and morpho-agronomic characterization combined with genetic dissimilarity analysis is essential to identify promising accessions, preserve genetic variability and support breeding programmes. It is also known that traits such as fruit mass and dimensions are among the most relevant for differentiating genotypes and guiding parental selection. What are the new findings? This study characterized, for the first time, 16 tomato accessions from different Brazilian AGBs (UFV and Embrapa Hortaliças) using 33 qualitative and nine quantitative descriptors, revealing high genetic variability among them. The mass of 10 fruits (98.62%) and fruit width (0.99%) were the traits that contributed most to genetic dissimilarity. The most genetically similar accessions (BGH-6909 and BGH-6908) and the most distant ones (CNPH-1120 and BGH-6895) were identified, providing strategic information for future crosses aimed at heterosis. What are the expected impacts on horticulture? The results strengthen the knowledge base on tomato germplasm available in Brazil and provide direct support for breeding programmes, enabling the selection of more divergent and market-oriented parental lines. The practical application of these findings can lead to cultivars with higher yield, improved fruit quality and better adaptability, contributing to the diversification of commercial types and the conservation of genetic variability—key factors for the long-term sustainability of horticulture.