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Poster communications

Testing French Douglas-fir seed orchards: a newly established network of trials

Abstract : Tree breeding provides a major contribution to stand productivity and timber quality enhancement. Indeed, forest tree varieties simultaneously incorporate improvement for several traits related to site adaptation, growth, form and wood quality. Improved varieties, generally produced by sexual reproduction in seed orchards, are presently available for many forest species.A lot of trials demonstrate genetic selection effectiveness and the superiority of improved varieties over controls. Nevertheless, the genotypes planted in seed orchards have been individually selected for only a part of the characters that determine tree value. Moreover, they have been selected in a limited number of sites and under a climate probably different from the climate that the next generation of trees will experience in their lifetime. Therefore, field testing of improved materials is essential to quantify genetic gains, assess the performances for non-selected characters, study genotype x environment interactions and specify the areas where the varieties can be used safely and advantageously.In France, a programme of seed orchards was supported by the Ministry in charge of forests in the second half of the 20th century. INRA, Cemagref and ONF (French Forest Service) were the main actors. Currently, the productive orchards are operated by a consortium of two seed dealers (Vilmorin Company and ONF). The whole programme concerns 8 species among which Douglas-fir that is the 2nd reforestation species considering the number of traded seedlings. In the 1980's, eight clonal orchards were planted over 85 ha in SW France. Their components were selected within American natural populations (mainly Washington and Oregon but also California for an utilisation in dry regions) and in French selected stands. These orchards are now intensively managed and they currently produce 87% of the seedlings used in France.For years, improved seed of Douglas-fir have been produced by two orchards whose performances were well known. Yet, the prospect of climate change incited the seed dealers to diversify their supply with seeds now available from six new orchards. As little is known about their behaviour, four French organisations of research and development (Cemagref, INRA, ONF, CNPF) gathered together to test the whole set of Douglas-fir orchards in various conditions of soil and climate and in comparison with the seed zone Washington 403. A special attention has been paid to seed lot representativeness i.e. clonal cone collections have been organised in several orchards where cone production was unevenly distributed among clones.29 trials were established between 2009 and 2011. They are distributed in four categories of sites: i) areas where Douglas-fir is widely cultivated and should remain appropriate in the 21st century ii) mountainous areas (1000-1300 m a.s.l.) that climate change should make favourable to Douglas-fir iii) and iv) climatic marginal areas that are expected to be unsuitable for standard varieties (north of the natural Douglas-fir range) around 2050 (type 1) or are already too harsh (type 2).The trials have a single-tree plot (TSP) design (96 seedlings per genetic unit) or a block design (49 seedlings x 4 blocks). The ratio TSP/block depends on the site and whether a response is expected at juvenile or adult stage. Furthermore, demonstration trials have been established in order to facilitate spreading of information among private owner community.Though young, the Douglas-fir seed orchard testing network has already produced useful results. In particular, the 8 varieties have been ranked for lateness of bud flushing and, thus, sensitivity to spring frost. Sums of degree-days required for flushing have been computed. Data have also been collected for seedling health, polycyclism and initial height growth.In the long term, this network will give information on adaptability, growth and form of French improved varieties of Douglas-fir. As the trials are established in a large range of environments, the results should also provide useful information to foreign silviculturists.
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Poster communications
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https://hal.inrae.fr/hal-02596024
Contributor : Migration Irstea Publications <>
Submitted on : Friday, May 15, 2020 - 8:39:30 PM
Last modification on : Monday, May 17, 2021 - 4:54:02 PM

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  • HAL Id : hal-02596024, version 1
  • IRSTEA : PUB00033621

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G. Philippe, J.C. Bastien, S. Matz, G. Archevêque, S. Girard, et al.. Testing French Douglas-fir seed orchards: a newly established network of trials. Applied Forestry Research in the 21st century, Sep 2011, Prague-Pruhonice, Czech Republic. pp.1, 2011. ⟨hal-02596024⟩

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