Elche and Bari pomegranate collections: conserving local varieties and international germplasm for future challenges

The pomegranate (Punica granatum L.) is one of the oldest domesticated fruit species, resulting in a wide range of local cultivars worldwide. Spain and Italy are the leading producers and exporters in the European Mediterranean region, but developing new, well-adapted varieties is essential to maintaining competitiveness. Germplasm banks are key to conserving and improving this species, with the collections in Elche (Spain) and Bari (Italy) serving as strategic resources for the characterisation and use of pomegranate diversity in Europe. However, to maximise their value, comprehensive studies of the genetic diversity contained within these collections are necessary. This study evaluates the genetic diversity of both collections using 16 microsatellite markers and pomological data, providing an integrated overview of their genetic resources. Genetic redundancy between the two collections was assessed with the aim of improving collection management and identifying genotypes with the highest potential for breeding programs. A total of 185 pomegranate accessions were analysed — 94 from the Elche collection and 91 from Bari. The number of alleles per marker ranged from 3 to 13, with an average of 5.75 alleles per locus. Polymorphic Information Content (PIC) values ranged from 0.179 (PGCT022) to 0.654 (PGCT111), indicating substantial genetic variability across both collections. Phenotypic differences were also noted, especially in harvest time and fruit quality traits such as aril and peel colour, seed hardness, titratable acidity, and soluble solids. Both collections hold high genetic and phenotypic diversity, making them valuable for pomegranate conservation and breeding. Some genetically identical accessions showed phenotypic variation, underscoring the importance of combining molecular and morphological data. This study enhances our understanding of European pomegranate diversity and supports future breeding efforts by optimising germplasm management and selection.