Spatial Pattern of the Mitochondrial and Chloroplast Genetic Variation in Poland as a Result of the Migration of Abies alba Mill. from Different Glacial Refugia

Currently, the information on the gene pool of silver fir (Abies alba Mill.) at the northeastern edge of its distribution in Poland is scarce and insufficient. Using the advantage provided by markers with different modes of inheritance, a hypothesis that gene flow via both seeds and pollen contributed to the genetic structure across the entire analyzed region was investigated. The geographic distribution of maternally inherited mitochondrial DNA (mtDNA, nad5-4) and paternally inherited chloroplast DNA (cpDNA, psbC) variation was studied in 81 Polish populations and three reference populations from Ukraine and Romania. The spatial pattern of mtDNA haplotypes (dispersed via seeds) indicated that the Apennine Peninsula was the only maternal glacial refugium for the entire territory of Poland and also the Ukraine no 1 population, whereas the other two populations—Ukraine no 2 and Romania—had the haplotype representing the Balkan origin. By contrast, the cpDNA haplotypes (dispersed via pollen) from all studied Polish and reference populations showed that A. alba colonized the current natural range from two genetically distinct glacial refugia located on the Apennine and Balkan peninsulas. The occurrence of cpDNA haplotypes varied among the studied populations. Additionally, statistical analyses were used to infer the genetic structure of examined populations. Two distinct groups of A. alba populations were identified showing the postglacial geographic distribution of haplotypes of both mtDNA and cpDNA. A. alba is an important ecological and economic component of forest ecosystems in Europe. An understanding of the Holocene history of this species is relevant for planning sustainable forest management, and acquired data can contribute to strategies of conservation and restoration.