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ŠUMARSKI LIST 13/2011 str. 39     <-- 39 -->        PDF

M. Ivanković, M. Popović, I. Katičić, G. von Wuehlisch, S. Bogdan: KVANTITATIVNAGENETSKAVARIJABILNOST... Šumarski list – Posebni broj (2011), 25-37

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).

Regression analysis of the provenance mean values and Ellenberg’s climate quotients of
their source stands were shown (Figures 8, 9, 10). The aim of this analysis was to determine
relationship between genetic variability and climatic variables. Weak and statistically insignificant
correlations between height/survival and climate quotients were determined. The
same results were obtained using real and age corrected data. These traits were under the
strong influence of age differences that have accidentally been associated with the geographic
position of provenances (western older than eastern). It was most probably the cause of
the obtained geographic structure.

On the other hand, the age corrected values of winter leaf retention were significantly
correlated with EQ’s. There was gradual (clinal) differentiation of populations in the west-
east direction (the frequency of trees with dead leaves retention gradually decreased from
west to east) and declining trend of trees with leaves retention associated with an increasing
continentality (Figure 9). It should be mentioned that western provenances were older than
eastern ones and the increase of EQ’s was moderately correlated with geographic position
of provenances (EQ’s of eastern provenances were on average higher than western). For
these reasons, differences between provenances in percentage of trees with winter leaf retention
are more likely attributable to their age differences, rather than genetic differentiation.

Geographical structure of genetic differences between provenances was not shown for
flushing phenology. Results indicate an ecotypic (random) pattern of interpopulation differences
(Figure 6). There was a statistically significant correlation between provenance mean
values and Ellenberg’s climate quotients (EQ’s). Provenances from wetter and cooler habitats
(EQ=12-16) were later flushers. With the increase of continentality, provenances showed
a trend of earlier flushing. The peak of this trend was observed at the EQ=26, after
which the provenances showed a reverse trend, i.e. again flushing later (Figure 10).

Despite the fact that differentiation was not detected for traits which were influenced by
age differences (height, survival and winter leaf retention), it is more likely that population
differentiation in South-East Europe has ecotypic pattern that is shaped by macroclimatic
adaptation. This assumption is based on similar studies by other authors (Matyas et al.
2009), but also on our own results for the flushing phenology.

It can be recommended that European beech seed zone delineation and use of its forest reproductive
material should be done accordingly to ecological besides the geographic criteria.
Key words: provenance trial, growth, flushing, winter leaf retention, ecotypic variation,
macroclimatic adaptedness