Comparative spatial genetic structure of C. sativa cultivated varieties vs wild populations across Europe

Castanea sativa is a multipurpose species widely distributed across Europe. Man has influenced the structural and genetic characteristics of chestnut populations through propagation and transplanting, intensive cultivation and selvicultural practices. The goals of this study were to 1) evaluate the genetic diversity and gene flow of wild and cultivated populations at wide and local scale 2) identify possible alloctonous material as a result of human domestication activities. Six natural and 8 orchard populations, were collected in three different geographical areas Six nuclear microsatellite markers were used for the molecular analysis. Observed (Na) and effective (Ne) number of alleles, observed (Ho) and expected (He) heterozygosity, were calculated using the program GeneAlEx 6. Population structure analysis was conducted using the software STRUCTURE 2.3.3. The geospatial structure of chestnut populations was visualized using ArcGIS 9.3 software Orchard populations compared to natural stands showed lower values for all gene diversity parameters. In some cases, the structure analysis reveals the same gene pools for natural and orchard populations collected in the same areas, in other cases the orchard populations are genetically similar to natural population collected in distant geographical areas. The results were discussed considering the human activity and the different management of genetic resources.