Genetic Variability of two Fagus sylvatica (L.) Populations in the South-Western Edge of the Panonnian Plain

Two beech populations at altitudes of 273 m (Vrhovo) and 657 m (Kozarje), growing on significantly different forest site, in different ecological conditions and with different forest-management history were selected on Gorjanci Mountains and genetically investigated by means of isoenzyme analysis. A cline from minor to major allelic polymorphism was revealed at gene loci Aco-B, Idh-A and 6-Pgdh-A. At locus Skdh-A, allele A4 was observed only at the lower altitude population Vrhovo as a heterozygote genotype Skdh-A34 (12%). The Kozarje population of beech had a slightly higher genetic multiplicity, a slightly higher effective number of alleles per locus, higher observed heterozygosity and a higher level of intrapopulation differentiation. Statistically significant differences in the occurrence of alleles between populations were found at 5 of 16 loci. The average genetic distance of Gregorius (1974) was 6.1%. European beech populations analyzed from different altitudes on Gorjanci Mountains appeared to be genetically differentiated. The results presented are also discussed in the light of the climate change impact on forests.