A way to utilize the advantages of clonal forestry for Norway spruce?. Presentation by Dag Lindgren Finland 080910 at conference on Vegetative propagation of conifers Website connected to the meeting at http://www-genfys.slu.se/staff/dagl/Meetings/Finland08/VegPropFinland08.htm.
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at conference on Vegetative propagation of conifers
Website connected to the meeting at
Photo: Mats Berlin 2008
Take home message: sibs rather than tested clones
The gain of vegetative propagation is in the seeds,
not in testing the clones!!!!
Full sib family forestry – who could ask for anything more?
Photo: Anders Fries 2008
When selecting clones with known breeding values, a large gain is made. At least 6% for the first plus tree selection and an additional for selecting tested plus trees with high breeding values.
As more selections are required for a seed orchard than a few crosses, the selection gain will be higher for crosses.
It is untested crosses, the option to select among tested crosses is not available in this scenario.
Parents to stand seeds often grow close to each other and are related.
Controlled crosses or seed orchards recruit parents over landscapes and break the isolates, parents will not be related.
Selfing occurs at wind-pollination in stands and seed orchards.
Selfing is eliminated by controlled crosses.
A major thief of genetic gain in seed orchards is the non seed orchard contaminating pollen.
Half of all pollinations come from unimproved trees, thus the selection gain is reduced by ¼ in seed orchards.
Controlled crosses eliminate pollen contamination.
This was if efforts started simultaneously, but there are timining differences.
There are too few spruce seed orchards, the alternative to crosses is stand seeds, and the gain by crosses will be 27% till a new seed orchard get full production at age 20.
The superiority will then sink to 11%.
The next cycle of long term breeding will generate 8% better clones, and crosses among them will be 19% superior, when the seed orchard is 30 years. A new better seed orchard will be growing then, but has not replaced the earlier one.
ATTACK OF THE CLONES stand seeds)
Photo: Dag Lindgren 1977
Controlled crosses in Aborgen taeda seed orchard (Charleston).
This company heads for 100% control cross (without vegetative amplification). The extra cost is justified!
Photo: Dave Gerwig
This is a genetically thinned seed orchard made from cuttings (Lagan), pruned to a convenient height for crosses. A thinned archive with the best clones preserved for crossings could look the same….
Photo: Anders Fries 2008
Potted spruce grafts for crosses in a green house (Ekebo, photo: Bo Karlsson)