Allozyme and chioroplast (cpDNA) variation was examined in five Italian and two Greek populations of Pinus teucodermis Ant. to estimate levels of genetic variability within and among populations and to establish the usefulness of allozyme and cpDNA markers in the taxonomic classification of these populations. Twenty-three isozyme gene loci were analysed, as well as restriction fragment length polymorphisms at two cpDNA spacer regions between tRNA genes.The level of genetic variability tended to be lower in the Greek populations but overall the observed levels of allozyme variation within and among populations were similar to those of other conifers. Identical cpDNA amplification and restriction patterns were observed among all individuals sampled from the seven populations. Taken together, the results of the allozyme and cpDNA analyses indicate that all seven populations belong to the same biological species.

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SummaryThe terpene composition of cortical tissue in five Italian populations of Picea abies K. has been analyzed by headspace gas chromatography. The results of analysis of variance showed significant differences in content of most terpenes between the populations. Because intensive sampling is required for description of the natural variability of forest trees, the application of headspace gas chromatography may provide many opportunities in genetic research.

Outcrossing rates were estimated in two artificial stands of Pinus leucodermis, a wind pollinated conifer characterized by a relatively high level of selfing. Multilocus outcrossing rates, estimated by assaying five enzyme loci, were lower than 86% in the two stands, using both dormant and germinating seeds, and not different from those observed in two natural populations located in the same area. The lack of relevant differences between single-locus minimum variance means and the multilocus outcrossing rate estimates observed in both the artificial stands indicates that most of the apparent selfing is probably caused by actual self-fertilization. The presence of a high level of self-fertilization in this species seems confirmed also in artificial stands, where the density is higher and neighbourhood structure should be less pronounced. The high level of self-fertilization found in P. leucodermis, which is probably due to the presence of a reduced number of recessive embryonic lethals as a consequence of genetic drift, could represent a selective advantage for this pioneering and precocius species. Key words: mating system, outcrossing rates, artificial stands, Pinus leucodermis.