"The STONE project addresses scientific issues related to stone fruit (Prunus species) biodiversity. In a worldwide competitive context, stone fruit breeding programmes have to face new challenges regarding the maintenance of high quality fruit production under a changing climatic environment and increasing threats from pathogens, especially the sharka disease. STONE is a four years coordinated joint programme of staff exchange for short and medium periods between two European organisations, an associated and two ICPC third countries. The IRSES scheme is designed to provide opportunities of mobility to researchers and support research organisations. It integrates existing bilateral collaborative activities into a coherent long-term multinational programme addressing a key issue to two high priorities on the political agenda of the EU, i.e sustainable agricultural fruit production and biodiversity. The programme of exchange is intended to develop common tools and to jointly use these tools for the comparison of the genetic biodiversity in the European, Caucasian and Central Asian Apricot, Peach and Cherry germplasms. The project objectives include the assessment of the genetic diversity at selected loci directly affecting response to virus infection and to climate changes. The range of common fruit tree species of interest and of climatic conditions, as well as the strategic importance of fresh fruit production in all the countries involved will provide a coherent framework and socio-economic background for the planned research activities. Three topics have been identified as most relevant for all partners involved in the STONE project: assessment of the broad genetic diversity at the centers of origin and along the expansion routes of Prunus species after domestication and analysis of the genetic variability at loci related to Plum pox virus resistance and at loci controlling winter chilling-dependent floral induction."