DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 1-2/1966 str. 171     <-- 171 -->        PDF

b) Hybridization between broad leaved species. Works on controlled
crossings are hardly in progress. However, the seed of spontaneous and sub-
spontaneous crossing of plus trees has been used for the production of the planting
stock intended for progeny tests.


The Institute for Dendrology and Genetics of the Forestry Facility, Zagreb, is
engaged in the improvement of Quercus robur by applying intraspecific controlled
pollination in Q. robur f. typica x Q. robur f. tardissima. Produced were plants
from the spontaneous and subspontaneous hybridization of this species.


Less work has been done in the domain of broadleved species improvement than
in conifers. However, here is not meant the work on Poplars and Willows, which
will be discussed separately.


In the Institute for Forestry and Timber Industry, Beograd, was carried out
an experiment with the self-fertilization in Locust-tree. It was shown that this species
is self-sterile. The same phenomenon was investigated in Lime-trees, and it
become apparent that they too are to some extent self-sterile because a high percentage
of unfruitful seed could be obtained (43).


Investigators from the Forestry Faculty, Beograd, established that the monoecious
Black Poplar is to a great extent self-sterile. The usability of the seed lasts
20 days after which it decreases considerably. Its inbred seedlings are very susceptible
to fungal diseases if compared with the control seedlings of Black Poplar. The
inbreeding in the Fi generation in 2-year-old plants keeps continuing by a decrease
of the total production of vegetable matter. There appeared no morphological differences.


2. Hybridization between species
Works on the interspecific hybridization were on a wider basis.


a) Hybridization between coniferous species was carried out
in several research institutions.


The Institute for Conifers, Jastrebarsko, and the Institute for Dendrology and
Genetics of Forestry Faculty, Zagreb started with these activities in 1957. From the
crossing of Larix decidua x Larix leptolepis were produced several hundred hybrid
plants (15); the crossing of Picea omorika x P. sitchensis gave 50 hybrid plants (20);
from the crossing of Pinus nigra x P. densiflora were obtained 270 plants; P. nigra
x P. halepensis gave 12 seedlings of which survived 4 individuals (in juvenile stage
these hybrids resemble to the female parent of P. nigra). Lastly, from the crossing
of Pinus silvestris x P. densiflora were obtained 3 hybrid plants.


The Forest Institute, Skopje, commenced in 1962. an interspecific hybridization
with the mother trees of Pinus peuce, P. silvestris var. hamata, P. strobus, and Abies
alba (Fir of the Mt. Perister). Performed were the following crossings: Pinus peuce
x P. strobus, P. peuce x P. monticola, P. peuce x P. excelsa, P. peuce x P.
Lambertiana, and P. peuce x P. griphithii. From these crossings were obtained seeds
of two seed crops. This year we expect the production of hybrid seedlings. Crossings
of Abies alba x A. cephalonica, A. alba x A. concolor, A. alba x A. grandis, A. alba
x A. pinsapo, and A. alba x A. nordmanniana gave a few hybrid plants which are
under test. In 1964. were effected crossings of Pinus strobus x P. monticola, P. strobus
x P. peuce, P. silvestris var. hamata x P. nigra, P. silvestris var. hamata x P.
halepensis. In the crossing of P. silvestris var. hamata x P. halepensis. In the crossing
of P. silvestris var. hamata x P. nigra were chosen the individuals with equally
coloured male and female flowers (red x red, and yellow x yellow). These work´s
are being continued.


b) Hybridization between broadleaved species, as well as the
hybridization within these species have been carried out to a small extent.


The Institute for Dendrology and Genetics of the Forestry Faculty, Zagreb, laid


out experiments in connection whith the improvement of the Lime-tree. In 1964.


were effected interspecific crossings between Tilia platyphyllos, T. cordata, and T.


tomentosa. From the same species were produced the plants through spontaneous


and subspontaneous hybridization.


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