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ŠUMARSKI LIST 3-4/1973 str. 61     <-- 61 -->        PDF



I the paper are described the height and diameter growth, some seed characteristics
and resistance to brown spot needle blight (Scirrhia acicola) of the progeny
of Fi-generation (Pinus nigra X Pinus densiflora), of the progeny from backcrossing
Pinus nigia X (Pinus nigra X Pinus densiflora), as well the progenies from baccrossings
which were open pollinated (Pinus nigra X (Pinus nigra X Pinus densiflora)
X open pollinated).

On the basis of results of experiments laid out in the nursery and in the field,
the authors came to the following conclusions:

1. The Fi-generation of hybrids of Pinus nigra X Pinus densiflora stands better
transplanting than the pure Austrian Pine when transplants are 1+3 year-old,
and it exhibits a more vigorous growth at the age of 8 years.
2. Progeny from the backcrossing of the mentioned hybrid exhibits also a vigorous
growth than the Austrian pine at the age of 9 years.
3. Progeny of three hybrid families of the backcrosses exhibits a more luxuriant
growth than that of Austrian Pine at the age of two years. The size of seed
(length and thickness) of backcrosses is intermediate in relation to the parent
4. The phenomenon of a more luxuriant growth in backcrosses and in their progeny
in relation to the progeny of pure Austrian Pine may be explained by
means of the hypothesis of Wright et al., according to which there occurs a selection
during embryogenesis, which favours hybrid embryos.
5. Hybrids between Austrian Pine and Japanese Red Pine fructify already in early
youth, and in this respect they exhibit the phenonmenon of heterosis. Considering
that the backcrosses and their progenies display the phenomenon of heterosis,
and also that they are blooming early, and abundantly, plantations of hybrids
may also be used as seed sources.
6. Backcrosses of hybrid families are more resistant to brown spot needle blight
(Scirrhia acicola) than the progeny of pure Austrian Pine.
7. With respect to the mentioned conclusions, the authors are of the opinion that
the introduction of the investigated hybrid into plantations, especially into those
for the afforestation of degraded karst lands is promising. Therefore a further
study of this hybrid ought to be carried out both from the viewpoint of growth,
wood quality, resistance and comb´ning ability of parents, and the viewpoint of
the interaction genotype — environment.