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Recent changes in environmental conditions in populations of peat-bog pine (Pinus uliginosa Neumann) caused rapid decline or even extinction of the species in several stands in Central Europe. Conservation strategies for P. uliginosa require information about the evolutionary history and genetic structure of its populations. Using isozymes we assessed the genetic structure of P. uliginosa from four isolated stands in Poland and compared the results to genetic structures of other closely related pine species including eight populations of Pinus mugo, ten of Pinus sylvestris and one of Pinus uncinata. The level of genetic variability of P. uliginosa measured by the mean number of alleles per locus and average heterozygosity was similar to others related to P. uliginosa taxa from the reference group but it differs among populations. High genetic similarity was found between two populations of P. uliginosa from Low Silesian Pinewood. The populations were genetically distinct as compared to other populations including locus classicus of the species from the peat bog at Batorów Reserve. Very low genetic distance (DN = 0.002) and small genetic differentiation (GST = 0.003) were found between P. uliginosa and P. mugo in the sympatrie populations of the species from Zieleniec peat bog suggesting the ongoing natural hybridisation and genetic contamination of peat-bog pine from this area. Some evidence for skew in allele frequency distribution potentially due to recent bottleneck was found in population from Low Silesian Pinewood. The analysed open pollinated progeny derived from two P. uliginosa stands from Low Silesian Pine- wood showed the excess of homozygotes as compared to the maternal trees indicating high level of inbreeding (F =0.105,F = 0.081). The results are discussed in the context of evolution of P. uliginosa populations, taxonomie relationships between the analysed species and conservation strategies for active protection of peat-bog pine.
This study examined the anatomical and morphological variability of 10 needle traits in isozymatically identified clones of three peatbog populations of Pinus mugo, focusing on variation within and between clones, and the relation between isozyme variation and morpho-anatomical characters of needles. In each peatbog there were clones exhibiting high and low plasticity of the anatomical and morphological traits studied. In general, three types of variation within clones were distinguished: (1) clones with ramets very similar to each other, (2) clones with extensive intra-clone variability, and (3) clones with intermediate variability. The differences in phenotypic variability within clones may be explained by differences in the reaction norm of ramets in particular clones and by somatic mutations. In respect to anatomical, morphological and isozymatic traits, clones from the same peatbog showed more similarity to each other than to clones from other peatbogs.
The aims of this study were 1) to determine the variability in the flowering phenology of Scots pine (Pinus sylvestris L.) clones in a seed orchard and 2) to compare the genetic structure and genetic markers (13 isozyme loci and 5 chloroplast and 3 nuclear DNA microsatellite loci) among groups of clones that are differentiated by flowering phenology. Using the timing of male inflorescence development, 57 plus trees represented by their clones in a seed orchard were classified into three phenological groups: early-, intermediate-, and late-flowering. The microsatellites showed no significant differences in the genetic structure of the analyzed phenological groups. However, the frequency of allele 2 at the shikimate dehydrogenase A locus (ShDH A 2) differed significantly between the groups of early- and late-flowering trees and between the groups of intermediate- and late-flowering trees. In addition, a significant difference in the frequencies of the genotype ShDH A 11 was observed between the intermediate- and late-flowering groups. Nei’s genetic distance indicated that the late-flowering group was the most genetically distant among the phenological groups. These results suggest that the ShDH A locus might be considered as isoenzymatic marker that differentiates these flowering groups of Scots pine clones. At several isozyme and DNA loci, the presence of private alleles in each group of pines was observed. However, these alleles cannot serve as markers of Scots pine flowering time because of their low frequencies.
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