Differentiation of beech stem forms using isoenzyme gene markers

Oriental beech (Fagus orientalis Lipsky) is one of the major components of the Iranian forests and it is of both ecological and economical importance. In beech stands (Fagus sylvatica Lipsky) it is observed, that beech trees with specific trunk morphology, such as forked stems, often occur in groups, can be assumed due to a limited pollen and especially seed dispersal and distinct family structures. Aim of this work was the investigation of a possible relation between the variability of the trunk morphology and genetic variation of the species. A total of 68 forked and monopodial trees in a beech stands in Hyrcanian Forests of Iran were analyzed using 16 enzymatic gene loci. Comparison for genetic diversity measures between the forked and monopodial trees revealed no significant differences for mean number of alleles per locus, mean number of frequent alleles per locus, effective number of alleles, neither for Shanon index nor expected heterozygosity. However, it was found private allele in the forked trees group, which is very important for adaptation processes in future. The outcrossing rate estimated using isoenzyme gene markers was relatively high for all of the investigated individuals, as expected. The results of this analysis did not show any clear genetic differentiation between the forked and monopodial groups of beech trees that means there was no indication about enzymatic genotypes, which strongly promote the formation of forked stems; this shows that application of isoenzyme gene markers in differentiation of adaptive treats should be considered with caution. However observation of private allele in forked trees group persuades us to continue this subject using other markers.