Evaluation of genetic differentiation of autochthonous sloe (Prunus spinosa, Rosaceae) populations across Germany using molecular markers

Background and aims - Sloe is a woody plant often used for plantings in the open landscape in Germany. As the use of autochthonous plant material is now required by the new German Nature Conservation Act six regions of origin have been designated according to eco-geographical parameters. As little is known about the actual genetic situation of most species affected by the new law we investigate the genetic diversity/differentiation of autochthonous sloe populations across Germany and discuss our findings with respect to conservation law and its practical implication. Methods - Fifteen autochthonous populations of sloe from all officially designated regions of origin were analysed using a highly reproducible high-annealing-temperature (HAT-) RAPD protocol. Genetic differentiation was assessed using distance based and Bayesian approaches. Key results - General heterozygosity detected within the populations was in the same range as described for other woody species (he 0.171-0.213). While the observed values of genetic differentiation between populations varied considerably (F-ST 0.025 - 0.226) the majority was found in the moderate range. Only two moderately differentiated genetic clusters were identified for sloe in Germany. Conclusions - Moderate genetic differentiation was observed between the two main clusters of sloe populations in Germany. Here, no strong evidence was found for isolation by distance (IBD) or by adaption (IBA). The genetic constitution of sloe populations across Germany rather seems to support isolation by colonialization (IBC) as the main driver of the moderate genetic differentiation in this species. The observed genetic differentiation and the geographic location of the identified genetic clusters only partially coincide with the designated regions of origin defined by German authorities for the implementation of the Nature Conservation Act. In our opinion, those regions can only be considered a first step in the preservation of genetic diversity. Upon availability of data on genetic structure and differentiation in a given species, the regions of origin should gradually be adapted to reflect those structures for each analysed species.