Structure of Genetic Variation and Implications for the Management of Seed and Planting Stock
This paper reviews what is known about genetic structure of forest trees, and how that knowledge is used to determine safe limits to the movement of plant material. Geographic genetic variation in adaptive traits is of greatest importance to concerns of seed movement. Genetic structure in adaptive traits may be ascertained through long-term provenance and progeny tests, or short-term common garden studies in a nursery or nursery-like environment. These studies have shown that variation patterns are not consistent among species, among regions within a species, or among traits. The first seed zones were developed based on differences in climate and vegetation, and did not account for differences among species. Seed zones were recently revised in Oregon and Washington to reflect current knowledge of geographic genetic variation for individual species. Seed zones are an administrative convenience that directs managers how to bulk seeds from different stands. The use of seed transfer guidelines, on the other hand, allows greater flexibility and better knowledge of the risks of seed movement. Transfer guidelines, however, require keeping track of many small seed lots, which involves more time and expense.
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Author(s): J. Bradley St. Clair, G. Randy Johnson, Jr.
Publication: National Nursery Proceedings - 2003
Event:
Western Forest and Conservation Nursery Association Meeting
2003 - Coeur d"Alene, ID
