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Tree breeding Activities for the yellow-cedar genetic resource management program involve genetic conservation, genecology, tree breeding, and technical support.
The following activities occurred over the last year: Progeny trials All 10 provenance test sites have been measured at 15 years. Results show continued evidence of weak geographic patterns. Changes to seed transfer will be proposed after complete evaluation of the data. Three annual series of clonal progeny have been established. Over 5000 clones from 400 full-sib families have been planted. Three to four test sites were established for each series. All sites have high survival and test trees are growing well. Five-year data were collected this fall from the first series. Clonal values from 1587 clones were calculated and officially released. Top selections have been repropagated in operational hedges. Clonal juvenility testing A clonal forestry project evaluated the most efficient technique for maintaining donor stock juvenility and thus rooted cutting quality. The study included over 100 clones that were established from seedlot 9777 every 2 to 4 years from seed and from previously rooted cuttings from the original seedlings. The oldest donors in the study were 18 years old. Another round of serial propagation was completed this year. Two series of trials from the hedges have been established. One series, established on 2 sites, is now 10 years old and we have collected data on growth, form and survival. The other series is established on two sites in coastal B.C. Analyses of nursery and field data to date indicate that clonal variation in rooting and stock quality is more important than juvenility. Whether a donor plant is continually hedged or periodically repropagated varies by clone. However, it must be stressed that all donor plants were healthy and reasonably juvenile, a prerequisite to a successful cutting program.
Pollen quality Continual monitoring of pollen development and viability at various natural yellow-cedar areas and “off-sites” have yielded some interesting results. Sites that have the coldest winter temperatures have the best pollen quality. As well, areas that have the warmest summer temperatures and the lowest number of frost-free days exhibit the worst pollen quality. Factors affecting yellow-cedar pollen quality may be a combination of:
Yellow-cedar decline In collaboration with the USDA Forest Service in Alaska, studies have been initiated to understand the basis of and to develop ways to mitigate yellow-cedar decline using adaptive variation among populations. This phenomenon has been widespread in Alaska over the past several decades, and is also impacting northern coastal sites in B.C., especially the North Island-Central Coast, Haida Gwaii, and North Coast Forest Districts, where the spread and severity of decline has increased noticeably. The main cause has been identified as mortality due to late-spring frost as climates have warmed in northern regions and insulating snow blankets have melted earlier, exposing fine roots in the upper soil horizons to temperature extremes.
Ministry Contact: Alvin Yanchuk |
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