QUANTITATIVE GENETIC VARIATION OF EUROPEAN BEECH (Fagus sylvatica L.) PROVENANCES FROM THE SOUTHEASTERN EUROPE

Since the genetic diversity of European beech (Fagus sylvatica L.) in South-East Europe (particularly for adaptive traits) is not well studied, the purpose of this paper is to determine the amount, pattern and possible causes of its adaptive genetic variability, through analysis of selected quantitative traits in a provenance trial. Research was conducted in a provenance trial in which thirteen provenances were analyzed (Table 1). The heights of all survived plants were measured successively after the first three growing seasons at the trial site, while flushing phenology and winter leaf retention were scored in the second and third year. The preliminary analysis showed that differences between provenances in the average values of height, survival and winter leaf retention were significantly influenced by age differences between provenances (due to different time of collecting seed and initial age of seedlings in the trial - Table 1), therefore the averages for the listed properties were corrected for "additive age effect". Analysis of variance was conducted in order to determine statistical significance of variance components caused by the effects of provenances. REG and CORR procedures were carried out to analyze the relationships between the investigated traits, as well as between the provenance mean values and climatic variables of their source stands (Table 2). Provenance means of real and age corrected traits are shown in figures 1, 2, 3, 4, 5 and 7. The results indicate high levels of genetic variability for all studied quantitative traits. Statistically significant differences were found between provenances (Table 3), but the real data for height, survival and winter leaf retention were impacted with their age differences. Statistically significant differentiation between provenances for height and survival were lost after the additive age effect correction. Between provenance differences for the analyzed traits were tested by Tukey-Kramer's test for a possible geographical pattern of genetic structure. Results indicated geographical structure for the height, survival and winter leaf retention in terms of gradual differences in the east-west direction (see Figures 3, 5 and 7). However, apparently clinal variability was primary influenced by age differences. Thus, existence of the variability cannot be confirmed. Moreover, geographical pattern disappeared after the age corrections for provenance mean heights and survival (see Figures 2 and 4). Regre