<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>New first and 1.5 generation seed orchards are to be created in Germany based on recently assembled breeding populations of <italic>Acer pseudoplatanus</italic>, <italic>Larix</italic> sp., <italic>Picea abies</italic>, <italic>Pinus sylvestris</italic>, <italic>Pseudotsuga menziesii</italic>, and <italic>Quercus</italic> sp. To justify the high expenses in time and cost for orchard establishment and maintenance, planning should make use of consolidated knowledge and experience of both the national and international scientific community. Here, we briefly describe advances in genetic gains achieved through tree breeding, and resume population genetic aspects and design considerations to draw conclusions for clonal composition and spatial design of the new orchards.</p>
<p>We conclude that to avoid outbreeding depression separate orchards are required for each breeding zone. The zones are species-specific and defined by ecological and climatic aspects. A minimum of 60-80 clones per orchard is recommended for native tree species with high proportions of natural regeneration in forest practice. This would allow future selective thinning based on estimated breeding values from progeny testing. It would also permit the transfer of seed orchard progenies into a naturally regenerating forest stands without the risk of a genetic bottleneck. Lower clone numbers are appropriate for non-native species and hybrids. It is important to strictly avoid inbreeding depression, achieved by using only one clone per progeny or population, from which the plus trees were selected. Further, the spatial layout should promote random mating by optimizing the neighbourhood of each clone. With all of these considerations taken into account, we expect superior quality traits and at least 10-15 % more volume from the new seed orchards.</p>
</abstract>

New first and 1.5 generation seed orchards are to be created in Germany based on recently assembled breeding populations of Acer pseudoplatanus, Larix sp., Picea abies, Pinus sylvestris, Pseudotsuga menziesii, and Quercus sp. To justify the high expenses in time and cost for orchard establishment and maintenance, planning should make use of consolidated knowledge and experience of both the national and international scientific community. Here, we briefly describe advances in genetic gains achieved through tree breeding, and resume population genetic aspects and design considerations to draw conclusions for clonal composition and spatial design of the new orchards.
We conclude that to avoid outbreeding depression separate orchards are required for each breeding zone. The zones are species-specific and defined by ecological and climatic aspects. A minimum of 60-80 clones per orchard is recommended for native tree species with high proportions of natural regeneration in forest practice. This would allow future selective thinning based on estimated breeding values from progeny testing. It would also permit the transfer of seed orchard progenies into a naturally regenerating forest stands without the risk of a genetic bottleneck. Lower clone numbers are appropriate for non-native species and hybrids. It is important to strictly avoid inbreeding depression, achieved by using only one clone per progeny or population, from which the plus trees were selected. Further, the spatial layout should promote random mating by optimizing the neighbourhood of each clone. With all of these considerations taken into account, we expect superior quality traits and at least 10-15 % more volume from the new seed orchards.

Towards new seed orchard designs in Germany – A review

Silvae Genetica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Towards new seed orchard designs in Germany \u2013 A review"}

New first and 1.5 generation seed orchards are to be created in Germany based on recently assembled breeding populations of Acer pseudoplatanus, Larix sp.,...

Towards new seed orchard designs in Germany – A review

Published Online: May 08, 2021

Page range: 84 - 98

DOI: https://doi.org/10.2478/sg-2021-0007

Keywords
Forest tree breeding, breeding population, plus trees, relatedness, inbreeding depression, outbreeding depression, heterosis, seed orchard design, clone number

© 2021 Heike Liesebach et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Towards new seed orchard designs in Germany – A review

Published Online: May 08, 2021

Page range: 84 - 98

DOI: https://doi.org/10.2478/sg-2021-0007

KeywordsForest tree breeding, breeding population, plus trees, relatedness, inbreeding depression, outbreeding depression, heterosis, seed orchard design, clone number

© 2021 Heike Liesebach et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Forest tree breeding, breeding population, plus trees, relatedness, inbreeding depression, outbreeding depression, heterosis, seed orchard design, clone number