To respond to the needs of sustainable agriculture and forestry, it is necessary to preserve, among the plant species of the Atlantic Area, significant genetic diversity. The European Chestnut (Castanea sativa), the production of which makes possible the maintenance of agricultural and forestry activities in traditional rural areas, is an essential species, but one menaced by various diseases. The CASTANEA REG project proposes to study, in an organised manner, the genetic diversity of the Castanea sativa species in the three regions of the project, in order to create an Atlantic Network for the Study and Conservation of the Genetic Resources of the European Chestnut, which will help protect the chestnut, both at the level of the three countries involved, and at the European level.