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ŠUMARSKI LIST 1-2/1968 str. 51     <-- 51 -->        PDF

of the mentioned characters in both populations was computed by means of the
linear regression »one parent (mother) — two-year generative progenies« (Graphs
2, 4 and 5).

On the basis of obtained results the following conclusions may be drawn:

1. On the ground of the analysis of stem heights in the populations at Lipovljani
and Bakovci and their generative progenies, it may be concluded that in this
case too one has a genetic variability. This conclusion was reached on the basis
of the highly significant differences for height in the grown-up Bakovci and
Lipovljani populations and in their generative progenies in favour of the reresentatives
of the Bakovci population.
2. We consider the greater heights of the representatives of the Bakovci population
to be conditioned by the presence of a greater number of heterozygous
individuals, or that the relatively smaller heights in the representatives of the
Lipovljani population are the result of a greater frequency of heterozygotes.
(We assume that the heterozygotes for the colour of shoots are also those for
the heights.)
3. Because of a great competition during the second growing period we did not
obtain realistic amounts for the heritability of heights. On the basis of the
computed heritability of 7°/o (Bakovci) and 6,5´% (Lipovljani) we obtained a
small genetic gain. On the basis of the range of variability with respect to stem
heights in the Bakovci populations we would expect greater genetic improvement
in this and the following generation than the one computed with AG —
0,31 m. Within the Lipovljani population we cannot expect a greater improvement
either in this or the following generations.

4. When computing the inheritance of the number of branches by means of the
linear regression »mother — progeny« we obtained for the Lipovljani population
a result greater than 100% (viz. 115´%). The result obtained is unrealistic and
can be interpreted by the presence of the maternal effect. We did not compute
the heritability of the mentinoed character for the Bakovci population because
in the calculation of the linear regression »mother — progeny« (number of
branches per running m.) we obtained a negative value for the regression
coefficient bi.
5. The results obtained for the heritability of the number of branches suggest that
the number of branches in White Willow (S. alba L.) is conditioned in a smaller
degree by heredity than by environment.