On the origins and spread of Olea europaea L. (olive) domestication: evidence for shape variation of olive stones at Ugarit, Late Bronze Age, Syria-a window on the Mediterranean Basin and on the westward diffusion of olive varieties

Charred archaeological stones of Olea europaea L. (olive) from Late Bronze Age Ugarit, Syria, were analyzed with geometric morphometry and compared with a morphological differentiation model established on the basis of analyses of modern spontaneous (uncultivated) olive populations and cultivated varieties of various origins within the Mediterranean Basin. The results allow a reinterpretation of the east-west morphological diversity previously observed in wild olives. The archaeobotanical data were compared in detail to the partly geographically structured modern morphological diversity of the cultivated olive. Ancient morphotypes could be distinguished, among which one is dominant in the assemblage. Their diffusion from east to west is shown, and their time of arrival in the northwestern Mediterranean can be evaluated by comparison to archaeological material from that area. Combining morphometric and genetic data, modern reference and archaeological material also guides us in understanding the mechanisms that prevailed in the long-term agrobiodiversity of the olive.