Determination of the origin of the rychtal Scots pine (Pinus sylvestris L.) seed tree stands using microsatellite markers

The rychtal pine is one of the most valuable ecotypes of Scots pine (Pinus sylvestris L.) approved for the breeding purposes in Poland. However, it occupies stands typical for oaks and beeches as shown by the compatibility analysis of species composition in relation to the habitat type in which they occur. Such result raises some doubts in terms of the naturalness of the rychtal pine and calls its history and origin into question. In the present study, we used the set of nuclear microsatellite markers to characterize and compare the gene pool composition of the selected seed tree stands of the rychtal pine with 200−year−old pine trees which grow at the Syców Forest District (SW Poland). We aimed to know to what extent the set of alleles specified for the group of the oldest trees from natural habitats is represented in the younger forest tree stands of the rychtal pine. The analysis of molecular variance (AMOVA) and clustering analysis showed that the gene pool of the studied pine populations was homogenous (FST=0,02%, K=1). The parameters of genetic variation were similar for all populations except for the mean number of alleles. On average, 25 new alleles were found in two rychtal pine seed tree stands as compared to the set of alleles found in the group of old pine trees. However, all alleles defined for old pines were also present in the gene pool of younger rychtal pine forest stands. The differences in the gene pool richness result most likely from quite high differences in the number of individuals analyzed from each population. In conclusion, our results indicate the common origin of the studied Scots pine populations