Mitochondrial and nuclear DNA differentiation of Picea abies populations in Poland

The natural stands of Norway spruce in Poland are split between the southern and the northeastern parts of the country. Two so-called "spruceless" zones separate the northern spruce locations from those in the south, one "spruceless" zone is situated in Central Poland, and the other one in the Beskid Mts. Mitochondrial (STS) and nuclear (SSR) markers were used to perform the genetic identification of Norway spruce. Four different variants of haplotypes, "a", "b", "c" and "d", were found to occur in the nad1 locus of STS markers. Populations from the northern range of Picea abies distribution in Poland harboured exclusively haplotypes "c" and "d", except for the Białowieża population which had haplotypes "a" and "c". Populations from the "spruceless" zones contained four types of haplotypes whilst those from southern Poland were mostly composed of haplotype "a". High mean gene diversity was observed for both STS and SSR markers (HT = 0.529, and HT = 0.851, respectively). The total genetic differentiation of Norway spruce populations was very low (FST= 0.088). Two main groups of populations were distinguished in the dendrogram defined by Nei's genetic distances based on microsatellite markers. The distribution of the genotypes was scattered and did not show any connection with the spatial distribution of P. abies in Poland. Only the mtDNA markers were able to differentiate the northern populations of Norway spruce from the southern ones, proving the historical separation between the Baltico-Nordic and the Hercyno-Carpathian ranges of P. abies in Poland. By contrast, the microsatellite data suggested an overlap between the genotypes due to the human manipulation of Norway spruce stands in the past.