Castanea sativa sweet chestnut ancient trees across Europe: sources of genetic diversity

Sweet chestnut ancient trees constitute a reserve of genetic variability, which can be considered a great resource for management programmes of forest species. The genetic characterization of these trees can be crucial to improve our knowledge of the molecular basis of local adaptation, identify selective drivers and explain the contemporary genetic variation of tree species. In this study, we performed a comprehensive field survey to uncover the occurrence of large old sweet chestnut trees in south-central Italy, Spain and Britain. Eighty-eight ancient chestnut trees were genotyped using nuclear microsatellites (SSRs) with the main goals of assessing their genetic identity and providing hypotheses on the origin of this germplasm. Our final objective is to contribute towards knowledge and valorisation of these large old trees of potential interest for both genetic improvement and conservation of European sweet chestnut.