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Since the beginning of XIX century a considerable number of Douglas fir populations from North America were introduced to many European countries. In France, Douglas fir is still going to increase significantly its participation in growing stock and wood harvest. There are also some countries (e.g. the Netherlands), where the interest in breeding and silviculture of Douglas fir have been decreased in last decades. The data from the European literature was collected to show a current volume stock, growth increment, gene resources and qualified seed sources of Douglas fir in the outlook of the future role of the species in European forest economy. A short outlook on the breeding programs of Douglas fir working out in several European countries was also presented.
Sylwan
|
1997
|
tom 141
|
nr 04
77-84
In 2004, abundant flowering of Norway spruce (Picea abies (L.) Karst.) was observed in two second- generation seed orchards: (1) ‘Outbreeding’, promoting crossing between clones of five geographically distant populations; and (2) ‘Kolonowskie’, restoring a population whose offspring exists only in an international experiment (IUFRO 1964/1968). In bothseed orchards, female strobili were produced by 91.3% and 91.7% of clones, represented by 64.1% and 55.5% of grafts, respectively, and statistically significant differences between clones were found in the number of mature cones. In the case of the seed orchard ‘Outbreeding’, the number of mature cones in individual clones was significantly correlated with latitude of the origin of maternal populations (r = 0.8826, p = 0.0470). The majority (95%) of cones in seed orchards ‘Outbreeding’ and ‘Kolonowskie’ were produced by only 28.2% and 38.5% of all clones, and 21.4% and 25.7% of all grafts, respectively. These data attest to a disparity between the level of genetic diversity in seed orchard progeny resulting from the observed numbers of cone-bearing clones and grafts and the genetic diversity expected from the actual participation of clones and grafts in seed orchard composition. The estimated seed production per 1 ha of seed orchard area in 2004 reached 21.05 kg for ‘Outbreeding’ and 21.72 kg for ‘Kolonowskie’.
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