Genetic and morphological variability among autochthonous Prunus spinosa populations in Flanders (northern part of Belgium) : implications for seed sourcing

Background and aims : Seed sourcing on a local scale is an emerging awareness among nature conservationists. Guidelines should be tuned for woody species in highly anthropogenic landscapes such as Flanders (Belgium). We investigated the genetic variation within and between eight autochthonous Flemish Prunus spinosa populations and assessed their potential as seed source for gene conservation and ecological restoration. Methods and key results : All sampled sites were old hedges or wooded banks.Using AFLP, the overall gene diversity (H-t) was estimated at 0.13, with a low average between population diversity (H-b = 0.02) and a comparatively high average within-population diversity (H-w = 0.11).The genetic differentiation was remarkably variable among populations (Phi(ST) ranging from 0.07 to 0.43). There was no clear relationship between genetic and geographic distances, nor between genetic and morphometric characteristics. Only a small but significant correlation between endocarp and leaf morphological characters was observed. Conclusions : The variable genetic differentiation among populations points to different vegetation histories. Two populations, DEF and WES, were characterized by a dominant presence of sloe, high genetic differentiation from all other populations and low within-population diversities. No obvious morphometric variability of leaves could be related to these genetically deviating populations, however, WES showed a deviating endocarp morphology. Possibly, these two populationswere originally planted or supplemented using local and much related material whereas the others may have been planted with more diverse material. The relatively high within-population diversities and moderate, although variable, between-population differentiation of the other Flemish populations point to a considerable amount of gene exchange and can justify extensive seed sourcing for the production of autochthonous planting stock.These results stress the importance of a proper evaluation of genetic diversity for seed source selection and the need for regional field-applicable guidelines