Genetic diversity of Italian populations of Abies alba

Abstract Silver fir (Abies alba) is a common tree species in the mountainous areas in Europe. A number of natural stands in the hilly regions of northern Europe represent relic populations. The aim of the research was to evaluate the diversity present in Italian populations of the species. Genetic diversity was assessed in 45 silver fir populations covering the species' distribution range in Italy, based on the allelic variation present at seven microsatellite loci (SSRs). A consistent level of intra-population variability was present. Several of the populations displayed signs of ongoing genetic erosion, and evidence for a recent bottleneck in some was identified. Populations from the eastern Alps and the Apennines were more variable than those sampled from the western Alps. About 8% of the overall genetic variance was found between populations, with the remainder representing variation present within the populations. The data suggested that the southern Apennines acted as a refugium during the most recent Ice Age, and that many of the populations from this area have remained isolated over a prolonged period. Smaller and more isolated populations have experienced genetic drift, whereas the larger ones have preserved a high level of diversity. Identification of genetically homogeneous regions could be informative for the management of genetic resources.