Phenotypic and molecular diversity in a collection of 'Pomodoro di Sorrento' Italian tomato landrace

- SNPs genotyping and morphological traits discriminated 'Pomodoro di Sorrento' tomato landrace.
- 'Sorrento' accessions were distinguished into two different morphotypes based on fruit morphology.
- Two SNPs showed a strong correlation with Verticillium wilt resistance/susceptibility traits.

The 'Pomodoro di Sorrento', originating from Southern Italy, represents one of the most important and remunerative Italian tomato landraces for “fresh market”. Despite its outstanding organoleptic and nutritional qualities scanty information still exists on the structural variation of this traditional tomato. Here we report the evaluation of ten accessions of the 'Pomodoro di Sorrento' tomato at phenotypic and molecular levels in order to provide a basis to unequivocally distinguish them from those belonging to the other most famous similar landraces grown in Italy. Morphological characterization based on 13 descriptors highlighted the presence of a significant level of variation for puffiness, green color and green shoulder of unripe fruits, allowing distinguishing two 'Sorrento' morphotypes. Genome-wide SNP genotyping was carried out using the ILLUMINA Infinium tomato array and revealed a genetically well defined structure of the 'Sorrento' landrace with respect to the other multilocular landraces most widespread in Italy. In particular, 1450 SNPs resulted polymorphic among 20 tested genotypes, and one clearly distinguishes the 'Sorrento' from other similar landraces. Finally, resistance assay to Verticillium wilt allowed the identification of promising 'Sorrento' accessions. Interestingly two markers localized into the Ve2 gene showed a strong association with the resistance/susceptibility trait. Taken as whole, our results provide a description of 'Pomodoro di Sorrento' landrace diversity, which provide useful information for its utilization in breeding programs as well as for its direct use in quality markets.