BreedingCoastal Douglas-fir (0 - 900 m) Tree improvement efforts in coastal Douglas-fir were initiated in the 1950s with the pioneering work of Alan Orr-Ewing. In the mid-1970d, Chris Heaman started a diallel crossing project with 6-parent disconnected partial diallels that was completed over eight years. In each year an average of 8 diallel sets, each with 15 full-sib families, were planted on 11 sites for a total of 88 test sites in mesic to richer coastal Douglas-fir sites (EP 708). In these progeny tests, candidate trees were forward-selected, using an index of height growth and wood relative density to establish breeding and production populations.
Currently, the breeding population (360 genotypes) is sub-divided into 30 sublines, each with between 10 and 15 parents, for future testing and breeding. To increase efficiency (gain per time), a complimentary test design is used for subline testing. All parents in each subline are polycross tested to estimate GCA using a standard (average breeding value) polymix and at the same time, positive assortative mating, based on BLP breeding value estimates of forward selections, is used to create full-sib families within each subline. In 1989 and 2003, eight sublines each were established in tests: 4 GCA test sites and one field and one farm-field site of full-sib family blocks. Forward selections from these full-sib blocks have be made based on the GCA tests. Another 8 sublines were sown in 2005. Initial selections were made at age 8 from the top 3 families per subline with the best three progeny being grafted. Final selections will be made at age 11 to pick the best progeny of the best family for the production population. High-Elevation Douglas-fir (>700 m) In co-operation with Canadian Forest Products Ltd. (Patti Brown), 54 of 56 parents in their high-elevation Douglas-fir orchard (#116) are GCA tested as a basis for rouging orchards. Based on 4-year results, 20% of the parent clones were rogued from below and a further 20% were rogued based on age 7 BLP breeding value estimates. Final selections will be made at age 11. Gains for this orchard are expected to be around 7%, supplying roughly 500,000 seeds for the seed planning unit between 700 m and 1200 m. Submaritime Douglas-fir (coast-interior transition) Earlier work in this seed planning unit consisted of wind-pollinated genecology tests with seed collected along elevational transects and tested on five sub-maritime (SM) sites. Recently, a clonal seed orchard was established with roughly 100 phenotypically superior parents selected from the submaritime zone. To take advantage of the flowering crop due to transplanting, a GCA test to facilitate backward selections was planted in 2005 on three sites in the SM zone at higher elevations (>750 m). This orchard will be rogued to 15 parental clones based on the progeny test results and will be supplemented with forward selections from the genecology tests. Gain is expected to be above 8%. Other ResearchSite Effects on Wood Density In the second generation coastal Douglas-fir tests (EP 708), three sets of selected full-sib families were planted on 22 sites instead of 11. These families are considered the “overlap” families, as they span two test series. In order to study the effects of site variables on relative density, these overlap families were cored and analysed for relative wood density using the maximum moisture method. Key climate variables were significant in a linear regression to predict wood density: July precipitation (positive), mean annual precipitation (negative), and continentality index (positive). Provenance Testing and Climate Change Five series of Douglas-fir provenance tests are currently available. The test series were planted between 1958 and 1974, containing from 6 to 77 provenances planted on 3 to 23 sites. The data are primarily used to test and revise seed transfer guidelines as the oldest tests approach rotation age. We also aim to use these tests to evaluate effects of climate change as has been done with lodgepole pine. A large number of provenance tests have also been planted in Europe that contain local B.C. populations. We are attempting to obtain data from these tests for our climate change models. Realized Gain Trials
To evaluate volume gain in improved planting stock of Douglas-fir, five
tests were established in 1996: Campbell River, Spirit Lake north of Campbell
River, Lang Bay near Powell River, Roberston Creek near Mesachie Lake, and
Norrish near Harrison. Measurements were carried out in 2001. These tests were
established at four different planting densities ranging from 625 trees/ha to
3906 trees/ha using three levels of genetic improvement: “Wildstand” controls
with an anticipated gain of 0%, “Mid-Gain” families, representing the average
genetic gain expected in second generation seed orchards (roughly 12%) and
“Top-Crosses”, representing the best parents crossed with each other with an
anticipated genetic gain of 17% in height growth. Plots were planted as 12 x 12
square plots in each density-genetic level combination. 2001 heights showed that
the average gain of the Mid-Gain families over the Wildstand was 12% - as
predicted, while the Top-Crosses outperformed the controls by an average of 17%
over all five sites – again, as predicted. Competition effects due to spacing
are not obvious yet, but will be evaluated in detail as the stands develop.
Ministry Contact: Alvin Yanchuk |
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