GENETIC-VARIATION OF PINUS-BRUTIA FROM ISLANDS OF THE NORTHEASTERN AEGEAN SEA

The present study concentrated on Pinus brutia TEN. one of the main fo rest species of the Aegean islands and one of the most important low-e levation Mediterranean conifers. In this report the amount and structu re of genetic diversity of four Pinus brutia populations which forms a n integral prerequisite for breeding efforts and for the protection of the species genetic resources, is presented. One population per islan d was sampled from four islands of the north-eastern Aegean namely Les vos, Chios, Samos and Thasos. Seven isoenzymic loci (Dia-1, Idh-1, Lap -1, Mdh-1, Mdh-4, Pgd-1 and Pgi-2) were identified and used for the ev aluation of genetic variability in the above populations. Five of the loci studied were polymorphic, while a total of 17 alleles were detect ed. All populations presented significant amounts of genetic diversity and heterozygosity. The levels of genetic diversity parameters were h igher than those of earlier reports regarding this species, but in agr eement with values reported for conifer trees in general. Genotypic fr equencies of the population samples were in agreement with those expec ted from HARDY-WEINBERG expectations. Results also point towards the a bsence of inbreeding and random genetic drift. Most of the genetic div ersity of Pinus brutia (97.9%) was found within populations and only 2 .1% among populations. Most of the alleles studied were common for all populations. Some differences among populations were detected for rar e alleles. Populations present low values of NEI's genetic distance an d CAVALLI-SFORZA and EDWARDS' chord distance. Two groups were revealed in the respective dendrograms: the first group formed by the populati ons of Lesvos, Chios and Samos, and the second by the Thasos populatio n. The significance of these results in breeding and forest management practice is briefly discussed.