Overview

Coastal Tree Breeding

• Coastal Douglas-fir
• Western redcedar
• Yellow cypress
• Sitka spruce
• Western white pine (coastal)
• Western hemlock

Interior Tree Breeding

• Interior spruce
• Interior Douglas-fir
• Western larch
• Lodgepole pine
• Western white pine (interior)

Coastal Tree Breeding

Sitka Spruce (John King, Dave Ponsford)

Sitka spruce, Picea sitchensis, has been an under-utilized tree species for reforestation purposes on the coast due to its susceptibility to attack and damage by the terminal weevil, Pissodes strobi. Sitka spruce (Ss) is a valuable, fast growing tree species and is a preferred species for reforestation on many west coast sites. It is particularly useful on sites prone to brush competition and browsing by deer and elk. Biodiversity considerations could also be cited for planting more Ss. At present the Forest Practices Code guidebook Management of Terminal Weevils in British Columbia recommends that the use of Ss be limited in areas where weevil attack is anticipated, particularly in moderate to high weevil hazard zones. Weevil hazard zones estimates have been identified and are correlated to biogeoclimatic zone variants. This information can be found within the pest risk tables of A Field Guide for Site Identification and Interpretation for the Vancouver Forest Region, page 229.

Over 20 years of research by provincial, federal and university researchers has uncovered some valuable natural resistance to the weevil. Populations and individual Ss that demonstrate low susceptibility to the spruce weevil have been identified. Seed collections have been made from these naturally resistant stands (B+ seed) and highly resistant individuals are now included in seed orchards (A seed). B+ seed is currently available and while the highly resistant A seed is still limited (300,000 plantables in 2005) plans are to be able to provide enough seed for 3 million plantables annually by 2012. With the availability of this resistant planting stock, higher stocking levels of Ss can now be utilized.

Last year (2004) we established the first phase of the F1 breeding program - weevil resistance. Parents were designated by their phenotypic resistance to the weevil and their source (mainly Haney or Big Qualicum). Some susceptible parents were also used. The trials were established in the Adam's River drainage North Vancouver Island, and at Jordan River, South Vancouver Island. Another site that we held over was established this spring (2005) on the Queen Charlotte Islands. We sowed a second series of the F1's this spring to be established spring 2006.

Selection and breeding work continues but our focus in the future for the breeding program will be to identify parents for specific traits. They will still be field assessed for resistance after weevil augmentation but a more detailed microscopic evaluation is being undertaken in order to classify parents according to putative mechanisms. This is particularly valuable for 'constitutive' type of mechanisms such as sclereid cells or constitutive resin cells and we are working to extend these techniques to look at some of the inducible mechanisms particularly traumatic resin cell production.

In the past we have relied strongly on the Canadian Forestry Service for entomology back-up to this program. With their new directions (and George Brown's retirement) we expect to rely more on the Universities, although Dr. René Alfaro still provides major input.

Ongoing trial assessments for weevil attack have continued, including some of the hazard assessment trials. These were a series of trials established to test resistance over a variety of ecological and potential weevil hazard areas. The main objective is to aid in determining deployment guidelines. This exercise will be carried out with the Coast Regional entomologist and silviculturist.

Besides the work with weevil resistance two other programs form part of the research on Sitka spruce genetics. The Queen Charlotte program allows us to assess Sitka growth free from weevil attack and supports the Seed Orchard program (SO 142 and its replacement). Our major difficulty has been in getting "free-to-grow" conditions in this case not from weevil or brush but from deer browse and a good deal of our maintenance effort is on browse protection

The transition program is in Northwest B.C. in the area where Sitka naturally hybridizes with white spruce. It is designed mainly to test seed transferability in a very environmentally heterogeneous area with pressures from both frost and weevil.

Major recent articles published include:

King J.N. and Alfaro R.I. 2004. Breeding for resistance to a shoot weevil of Sitka spruce in British Columbia, Canada. In: Carson, M.J., C. Walter eds. Plantation Forest Biotechnology for the 21st Century. 2004 Forest Research, New Zealand.

King J.N., Alfaro R.I. and C. Cartwright. 2004. Genetic resistance of Sitka spruce (Picea sitchensis) populations to the white pine weevil (Pissodes strobi): distribution of resistance. Forestry 77:269-278.