White Pine Blister Rust in British Columbia III. Effects on the Gene Pool of Western White Pine

Cluster analyses of relative terpene abundance in foliage of western white pine (Pinus monticola Dougl.) trees from throughout the Pacific Northwest geographic range of the species were produced. Terpene patterns were randomly distributed among populations; no geographic or site trends were evident. Although blister rust is devastating to stands, the gene pool is widely distributed and may well be preserved without establishing gene banks.About 40-50 trees selected at random would yield offspring with nearly all possible terpene patterns characteristic of the species and would thus constitute a broad genetic base. Therefore seed orchards do not necessarily need to be composed of many individuals, rather, they should contain highly selected individuals with multiple desirable traits including multiple blister rust resistance mechanisms. Key words: terpenes, dendrogram