Compatibility of breeding for increased wood production and longterm sustainability: the genetic variation of seed orchard seed and associated risks.

Abstract

Because breeding imposes strong artificial selection for a narrow suite of economically important traits, genetic variation is reduced in seedlings derived from operational seed orchards. Both quantitative genetics theory and studies of allozyme variation show that seed orchards contain most of the genetic diversity found in natural populations, although low-frequency alleles are often absent from seed orchard populations. Because plantations established with seed orchard seed are frequently maintained for only a single generation, they do not need to preserve the low-frequency alleles that are maintained in the breeding and gene resource populations. Moreover, in the Pacific Northwest, low-frequency alleles are typically maintained in the breeding population and in in situ reserves that serve as gene resource populations. Our analysis of theoretical and empirical data indicates that seed orchards with 20 or more selections should provide the same level of risks as seed collected from the natural population.

Keywords

Genetic diversity, tree breeding, seed orchards, risks

Citation

Johnson, R; Lipow, S. 2002. Compatibility of breeding for increased wood production and longterm sustainability: the genetic variation of seed orchard seed and associated risks. In: Proceedings wood compatibility initiative workshop. 18: 169-179