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

Western White Pine - coastal (John King, Dave Ponsford)

The use of western white pine (Pinus monticola) has declined to very low levels due to its susceptibility to white pine blister rust (WPBR) and the subsequent reluctance by foresters to choose it for reforestation. The decline of the native population, combined with the lack of regeneration, has driven white pine down to a small fraction of the total forest composition despite its ecological and commercial value and usefulness as a substitute for Douglas-fir in areas subject to laminated root rot.

Levels of natural resistance have been noted in some individuals and populations and a program involving selection and seedling screening for WPBR resistance involving both the BCFS and Canadian Forest Service (CFS) based on this resistance has been initiated. Trees from this effort, have been selected from and have been established in seed orchards. Although some level of resistance has been achieved it is considered only 'partial resistance' (PR) based mainly on slow canker growth (SCG), and silvicultural interventions such as pruning are still advised.

Another type of resistance that originates from the USDA Forest Service seed orchard in Dorena, Oregon can confer 'total resistance'. This white pine possesses resistance to WPBR that is based on a single gene (known as "Cr2") and is often referred to as 'MGR' (Major Gene Resistance) white pine. This gene has a recognition feature that prevents the rust from entering the host completely - thus it is clean resistance and is not overcome by inoculum load. The dark cloud filling in the silver lining is that this MGR resistance will likely fail at some point in the future. This is due to the inherent dynamics of disease resistance that is based on a single host gene that can be overcome by the pathogen. The prediction is that MGR resistance will last about 40 years.

The program then, is still concentrated on improving the partial resistance by a recurrent selective breeding program. By combining PR mechanisms in MGR pedigrees we may be able to extend the duration of MGR protection. A strong research component is to find other types of strong resistance similar to the MGR resistance.

The breeding program has been strongly guided by Dr Rich Hunt of the CFS who has screened over 300 families. The best parents were designated as either Slow Canker Growth (SCG) or Difficult to Infect (DI). SCG or "slow rusting" trees occur more frequently than DI. Also included as parents were some of the best of the Texada trees and some Idaho, Interior, and Dorena trees. Most of the crossing for this program was conducted in the CanFor Seed Orchard in Sechelt. Patti Brown of Canfor is also the chairperson of the White Pine species committee of the Coastal TAC of the Forest Genetics Council.

From the program to date, we have over 200 F1 families in this recurrent selection program in sites on Texada Island, Sunshine Coast and Vancouver Island. Measurements of these trials including survival and growth should begin in 2006.

Recent publications on the white pine program include:

Hunt, R.S. 2004a. Blister-rust-resistant western white pine for British Columbia. Natural Resources Canada, Canadian Forestry Service Information Report BC-X-397.

Hunt, R.S. 2004b. Environmental and inoculum source effects on resistance of Idaho F2 western white pine in British Columbia. Can. J. Plant Pathol. 26:351-357.

Hunt, R.S., G.D. Jensen, and A. K. Ekram. 2004. Confirmation of dominant gene resistance (Cr2) in the U.S. white pine selections to white pine blister rust growing in British Columbia. Pp: 227-229 in Richard A. Sniezko, Safiya Samman, Scott E. Schlarbaum,and Howard B. Kriebel, eds. Breeding and genetic resources of five-needle pines: growth, adaptability, and pest resistance: 2001 July 23-27; Medford, OR, USA. IUFRO Working Party 2.02.15. Proceedings RMRS-P-32. Fort Collins, CO, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 259 p.

King J.N. and R. Hunt. 2004. Five-needle pines in British Columbia, Canada: Past present and future. Pp: 12-19 in Richard A. Sniezko, Safiya Samman, Scott E. Schlarbaum,and Howard B. Kriebel, eds. Breeding and genetic resources of five-needle pines, growth, adaptability, and pest resistance, 2001 July 23-27; Medford, OR, USA. IUFRO Working Party 2.02.15. Proceedings RMRS-P-32. Fort Collins, CO, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 259 p.

King J.N. and A. David (submitted). Genetic Approaches to the Management of Blister Rust in White Pines. J. For. Ecol. and Mgmt.