DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu



ŠUMARSKI LIST 5-6/1967 str. 45     <-- 45 -->        PDF

mentioned populations as well as in interspecific hybrids between White Willow and
Crack Willow. In the 25-year-old population of Bakovci were collected 110 samples,
and m the 70-year-old population of Lipovljani 67 samples. Samples were taken
from the populations by mean of the method of random sampling where the sample
was represented by one tree. In the generative progeny issued from the mentioned
populations and in the interspecific hybrids of White and Crack Willow the colour
of the shoots was studied in all the plants raised (Tab. 1). Classification of the colours
was performed on the basis of »Code universel des couleurs«.


The colours characterizing the grown-up populations at Bakovci and Lipovljani
and their generative progenies were also established in the progeny of an interspecific
hybrid (S. X rubens Schrank), which was free-pollinated and which represents
the Fa (Fn)-generation, on the basis of which we confirmed the assumption that the
grown-up populations at Bakovci and Lipovljani represent hybrid populations of an
introgression character of Crack Willow.


On the ground of the colour of the Fi-generation shoots, on the basis of the
frequency of the genotypes and in dependence on whether in the concrete case we
have to do with a discontinuous or continuous variability, an assumption was made
as to the number of gene pairs conditioning the colour of the shoots. The author
applied the chi-square test either proving or rejecting the assumption.


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


1. The width of the genetic variability of the colour of one-year shoots in the
grown-up populations at Bakovci and Lipovljani and in their generative progenies
during the vegetative rest includes a total of 5 variants, viz.: dark-red,
red, light-red, light-green with red hue and olive-green.
2. One-year shoots of White Willow (S alba L.) display a dark-red colour, Crack
Willow (S. fragilis L.) an olive-green.
3. The same phenotypes which characterize the grown-up populations at Bakovci
and Lipovljani and their generative progenies, also characterize the hybrid
population (S. X rubens Schrank) X unknown.
4. The frequency of individual variants is not the same in the population at Bakovci
and at Lipovljani. In the population at Bakovci red phenotypes are more
represented (the homozygous-dominant ones and heterozygotes), while in the
population at Lipovljani green phenotypes (heterozygous green ones and homozygous
green).
5. When crossing White Willow with Crack Willow and conversey, if they are
homozygous with respect to the colour of shoots, we obtain a progeny with
light-red colour, which means that these two colours in the offsprings of the
Ft-generation are inherited intermediarily
6. Colour of shoots is a polygenic character and most likely conditioned by two
gene pairs having a cumulative action.
7. Considering that the same phenotypes appear in the population at Bakovci, that
at Lipovljani and in the hybrid progeny (S. X rubens Schrank) X unknown, we
may conclude that the representatives of the White Willow population at Bakovci
an that at Lipovljani are also in possession of the genes of Crack Willow,
i. e. that in the mentioned case we have to deal with an ingression.