The Slovenian traditional plum germplasm and its diversity compared to the French National Plum Collection

Slovenia, due to its close historical, geographical and economic links with the Balkan Peninsula, has a long tradition of plum cultivation and utilisation. During the last decades, the loss of valuable indigenous genotypes due to Plum pox virus significantly narrowed the genetic base of the existing plum germplasm. In order to preserve genetic diversity and reduce its erosion, systematic collecting and careful conservation management are crucial. Considering fast changing climate, agricultural intensification and appearance of new pests and diseases, it is vital to implement efficient and sustainable breeding approaches that utilize highly improved (i.e., modern cultivars), traditional (i.e., old, traditionally grown cultivars) and primitive germplasm (i.e., primitive and wild genotypes). The present research was set up to investigate the genetic relationship and variability among 125 accessions belonging to three Prunus species (P. domestica, P. cerasifera and P. spinosa) representing the Slovenian plum gene pool, including some modern cultivars from other countries (e.g., Germany, Romania, Serbia, UK and USA). The most frequently present traditional plum genotypes found in Slovenia probably belong to the species P. domestica and its subspecies. Hence, our study focused on P. domestica genotypes maintained in an ex situ collection of the Slovene Plant Gene Bank (26) and was compared with several accessions from the French Plum National Collection (14). The two collections were studied with 11 SSR markers: UDP96-005, BPPCT034, EMPAS12, UCD-CH17, EMPAS06, EMPAS11, EMPAS14, BPPCT014, BPPCT025, CPSCT026 and CPPCT006. For both collections, a relatively high and valuable diversity was determined. Several accessions clustered in accordance with the widely accepted pomological groups, such as traditional prunes, greengages and mirabelle plums.