Chloroplast microsatellite analysis reveals the presence of population subdivision in Norway spruce (Picea abies K.)

Three chloroplast microsatellites (cpSSRs), previously sequence characteriz ed and for which paternal inheritance was tested and confirmed, were used t o assess their usefulness as informative markers for phylogeographic studie s in Norway spruce (Picea abies K.) and to detect spatial genetic different iation related to the possible recolonization processes in the postglacial period. Ninety-seven populations were included in the survey. Some 8, 7, an d 6 different size variants for the three cpSSRs, respectively, were scored by analysing 1105 individuals. The above 21 variants combined into 41 diff erent haplotypes. The distribution of some haplotypes showed a clear geogra phic structure and seems to be related to the existence of different refugi a during the last glacial period. The analysis of chloroplast SSR variation detected the presence of two main gene pools (Sarmathic-Baltic and Alpine - Centre European) and a relatively low degree of differentiation (R-ST of about 10%), characteristic of tree species with large distribution and prob ably influenced by an intensive human impact on this species. Based on our data, we were not able to detect any evidence concerning the existence of a dditional gene pools (e.g., from Balkan and Carpathian glacial refugia), th ough we cannot exclude the existence of genetic discontinuity within the sp ecies' European range. A large proportion of population-specific haplotypes were scored in this species, thus indicating a possible usefulness of thes e markers for the identification of provenances, seed-lots, and autochthono us stands.