Genetic diversity of olives in Croatia

The olive tree (Olea europaea L.) is an important fruit tree species in all Mediterranean countries, including Croatia, which is characterized by a fair number of indigenous, locally grown varieties, and by a rich heritage of wild olive trees still found on numerous islands along the Adriatic coast. In the framework of the project "Biodiversity and Molecular Plant Breeding", the samples of 223 olive varieties and wild olives were collected from different locations in the olive growing area and molecularly characterized using 12 SSR (Simple Sequence Repeats) markers. The results showed a unique profile for most cultivars and wild trees, except for three cases of synonymy, probably attributable to misnaming. Overall, the Croatian germplasm showed high genetic variability. The neighbor-joining dendrogram separated a group of wild genotypes originated mostly from the middle and southern Dalmatian islands. Cultivated genotypes mostly clustered together but they also showed relationship with wild germplasm. The results obtained underlined the richness of the genetic resources of the olive tree in Croatia, providing information for the protection of genetic material and monovarietal oils.