Résumé
Almond is one of the oldest tree crops in the Middle East. Traditional almond cultivars are auto-incompatible and they are sexually propagated. Sexual reproduction is considered being evolutionarily advantageous because it leads to genetically variable progeny that may be better suited to survive environmental changes. Thus, traditional cultivars are adapted to various local eco-geographical conditions and may be influenced by different natural processes and agricultural practices. In this study, we focus on the traditional cultivar named 'Khachabi' cultivated in Lebanon since centuries, in the aim of assessing the dynamics of its genetic diversity, within cultivar and among plantations. A total of 349 trees were collected from 15 plantations distributed across the country and analysed using 15 nuclear microsatellite markers (SSR), to investigate patterns of genetic diversity. We detected a high genetic diversity within plantations. The overall pattern of genetic differentiation was low (Fst=0.06), suggesting a high level of gene flow between plantations and a low genetic structure between plantations may be due to gene flow and farmer's seed sharing networks. Farmers seek germplasm from other sources engendering a long-distance, human mediated, seed dispersal. Overall results revealed that 'Khachabi' genetic diversity is a dynamic system resulting from the interaction between the biology of this cultivar and human practices.