Genetic improvement of volume and wood properties of jack pine: selection strategies
1990
Magnussen, S. | Keith, C.T.
Six selection strategies aimed at genetically improving volume production and wood quality factors such as density, heartwood content, and stem taper are compared in a 20-year-old jack pine progeny trial. Selection indices were computed under various assumptions about economic values of the traits under selection and with constraints on the magnitude and direction of expected genetic gain. Stem taper, wood density, and heartwood content were under strong genetic control; however, the low phenotypic variation of wood density limits its potential for genetic improvement. Heartwood content emerged as a trait amenable for rapid genetic improvement. Despite low heritabilities the prospect of improving size-related traits was promising due to substantial phenotypic variation. Economic weights were important for the selection outcome and good progress was reported in all traits when volume received the highest weight. It was feasible to limit genetic gain in individual traits to predetermined relative levels but the cost in terms of reduced gain in unrestricted traits was economically debilitating. Concerns about undesirable concomitant changes in wood density, heartwood, and stem taper when breeding is based solely on growth traits were not confirmed by our data.
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