GENETIC-STRUCTURE OF FAGUS-SYLVATICA L. POPULATIONS IN SOUTHEASTERN EUROPE

Genetic structure of 38 populations from southeastern Europe has been studied using 11 enzymatic gene loci (PX-1, PX-2, GOT-1, 6-PGD-1, SOD- 1 ACP-1, MDH-1, IDH-1, PGM-1, PGI-1 and MNR-1). Eight loci are polymor phic with gene diversity ranging from 0.179 to 0.461. Principal compon ent analysis (PCA) based on allelic frequencies extracted 4 groups of populations: Rhodopes; Shars-Pindus range; Dinaric Alps and low Pannon ic mountain ranges; Biokovo Mountain and Istrian Peninsula, well assoc iated with geographical and climatic conditions. The statistical signi ficance of this grouping was tested by discriminant analysis (DA). Alt hough all 4 derived groups have high and similar values of the total d iversity (respectively 0.250; 0.228; 0.282; 0.264), the share of loci which are more polymorphic varies from group to group. Presence of som e rare alleles also indicates the difference between them. The correla tions between estimated genetic differences and presumed occurrences d uring the glaciation and the postglaciation periods have been discusse d, especially microgeographical conditions and evolutionary history of beechwoods from isolated regions of Biokovo and Istria. Multilocus F- statistics have also been computed. Positive F-IT values for all group s of populations indicate some deficit of heterozygotes, while high F- ST values prove certain differentiation among them.