Genetic variability of Pseudotsuga menziesii (Mirb.) Franco in northern Poland

Among the introduced conifers, Pseudotsuga menziesii (Douglas-fir) appears to be one of the best- acclimatised species in its secondary range in Europe. This undeniable success was most likely the result of matching secondary growth conditions to the ecological requirements of the native pop- ulations. Nevertheless, our knowledge of the genetic structure of the first-generation is still incomplete, leaving uncertainty whether climate changes have influenced the genetic structure of the studied populations. The main aim of the study was to determine the genetic diversity of Douglas-fir populations in Total DNA was isolated from needles collected in five old-growth and one younger stand. Four nuclear microsatellite markers were applied coupled with standard methods of statistical analyses of population molecular genetics. The high genetic diversity of the five first-generation stands corresponds to the diversity of native populations while the younger stand is characterised by a significantly lower genetic variability and a higher inbreeding index. Genetic distance analysis indicates a distinct grouping into two clusters: young population and the first-generation old populations. Here, for the first time we present the results of genetic diversity analysis of this species in northern Poland - western part of South Baltic region. Our results suggest higher genetic distance between older tree stands and younger one. Additionally, the younger stand was characterise by inbreeding. Considering the limitations of the dataset low (number of tree stands), we call for a genetic veri- fication of the origin of artificial populations of Douglas-fir in Poland.