Authors: Tourvas, Nikolaos; Ganopoulos, Ioannis;Koubouris, Georgios;Kostelenos, Georgios;Manthos, Ioannis;Aravanopoulos, F.A. (Phil);

The genetic diversity of wild olive (Olea europaea subsp. europaea var. europaea) populations in the Mediterranean is endangered primarily due to the expansion of olive groves. In this study the genetic relationships between Greek wild olive populations sampled in nature and Greek cultivars originating from reference collections, were investigated. A total of 209 wild samples and 67 cultivar samples including all officially recognized Greek cultivars were analyzed by employing 10 microsatellite loci. Wild populations exhibited high levels of genetic diversity, while 39% of the number of alleles detected was found only in the wild germplasm. Inbreeding was observed within populations, probably as a consequence of their fragmented spatial distribution. Three gene pools of wild olive were revealed corresponding to the geographical areas of: Northeastern Greece, Peloponnese-Crete, and Epirus. Most cultivars clustered in a separate group, while the rest of them formed a heterogeneous group with membership coefficients akin to the three wild olive clusters. Furthermore, bidirectional gene flow was detected between populations of Peloponnese-Crete and one cultivar gene pool. Ex situ conservation and in situ protection in areas isolated from cultivar gene flow is proposed for the preservation of this diverse resource.