GENETIC/BIOCHEMICAL CHARACTERIZATION OF TOMATO GERMPLASM LOCALLY CULTIVATED IN APULIA (SOUTHERN ITALY) AND POPULATION STRUCTURE OF ITALIAN TOMATO BIODIVERSITY

Italy is a secondary diversity center for tomato (Solanum lycopersicum L.), where several local populations and landraces are propagated by farmers. We established a collection of 55 tomato accessions originating from the Apulia Region (Southern Italy), including six accessions named “Pomodoro di Manduria” (PM), yielding small-fruit tomatoes recognized as “traditional agricultural productions” (PAT) by the Italian Ministry of agriculture, and as “presidia” by the Slow Food Foundation. We explored the collection genetic diversity using the Tomato 51K Axiom SNP genotyping array; in addition, we determined several physico-chemical features of tomato sauces obtained by a selection of 21 accessions (pH, antioxidant activity and the content of soluble sugars, phenolic compounds and nine individual isoprenoids, including carotene and lycopene). Five out of six PM accessions were deemed genetically identical (IBS > 0.99). Consistently, the physico-chemical features of tomato sauces obtained from these five PM accessions were similar and clearly distinct from those of tomato sauces obtained from other accessions, with the notable exception of one synonymous accession (i.e. not named as PM but having a IBS with PM accessions > 0.99). An inclusive analysis of the genetic structure of Italian germplasm was performed by merging array data with whole-genome resequencing data of 35 tomato landraces, available at the NCBI Database. Non-parametric and parametric analyses of genetic structure indicated, among other, genetic differentiation between large and small fruited genotypes. Finally, we identified combination of alleles allowing the distinction of PM accessions. Overall, this study carried out within the framework of several Regional and National research projects (“Biodiversità delle specie orticole da frutto”, “Centro Nazionale per lo Sviluppo di Nuove Tecnologie in Agricoltura”, “Progetto di rigenerazione sostenibile dei territori colpiti da Xylella fastidiosa”) provides valuable information for the preservation and valorization of local tomato genotypes.