engleski

Genetic variability of the Croatian beechwoods

Background and purpose Many analyses of genetic structure of beech populations covered wide European range carried out so far by means of isozymes markers. All investigations show geographical patterns of genetic variation as a result of climatic specifities or postglacial migrations. Purpose of this investigation is to study genetic variability of beech in Croatia where it grows in different enviromental conditions because of a high degree of adaptability and makes stable conditions for many plant associations. The aim is to find relation between allelic frequencies at investigated loci and different climate region form which samles are collected. Materials and methods 21 Croatian beechwoods (Fagus sylvatica L.), covering large and geographically different areas, was studied using proteins markers - isozymes at 11 enzymatic 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. Each beech population was described by means of allelic frequency calculated on the basis of diploid genotypes and the total gene diversity. Based on these values populations was compared by statistical methods. Results Total mean gene diversity (Ht) is 0.273. 8 loci are polymorphic while 3 are monomorphic in most samples. Comparisons of populations from various geographical regions show that the greatest difference is between Pannonic range and Biokovo Mountain populations. Also, the populations from Biokovo and Istria, although part of Dinaric Alps, show great difference of polymorphism at some loci in comparison with other populations from this range. At loci PX-1, 6-PGD-1 and IDH-1 significant influence of altitude was observed. Preliminary comparison of genetic structure of beech from different plant associations based on discriminant analysis and Mann-Whitney test singled out 2 associations: Seslerio- Fagetum and Doronico-Fagetum. Conclusion In spite of differences in geographical latitude, types of soils as well as climatic characteristics, Croatian beech populations - Dinaric and Pannonic do not show significant differences except Istrian and Biokovo populations which are, although part of Dinaric Alps, separated what points out some specifity of these two areas. Here are developed 2 plant associations, Seslerio-Fagetum and Doronico-Fagetum, which are also separated from all others associations. Differentiation of Istrian and Biokovo populations is result of climate and isolation.

Fagus sylvatica; isozymes; gene variability; Croatia

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