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A White Spruce Progeny Test--Seedling Seed Orchard: 12th Year Progress Report

Two hundred thirty-nine open-pollinated progenies of white spruce were established in a combination progeny testseedling seed orchard near Grand Rapids, Minnesota. Characteristics evaluated included, total heights at 2-0 and 2-2 in the nursery and 9 and 12 years from seed (in the field); field survival 9 years from seed was included. Survival was just over 77 percent. Family mean heights were from 60 to 167 percent of the nursery test mean at 2-0 and decreased in variation to from 52 to 125 percent of the plantation mean at age 12. Narrow sense heritabilities (computed as four times the interclass correlation) were 0.27 at age 9 and 0.35 at age 12 and are comparable to earlier results with white spruce in Wisconsin. They exceed Canadian results probably because Canadian material represented a more narrow geographic base. Data suggest a possible relation between growth rates and climatic seed collection zones. Pending further study, nurserymen should not collect seed in the extreme climatic zones in northeastern Minnesota. Plans for conversion of the test to a seed orchard are described. Possible genetic gains of from 15 to 20 percent are predicted on the basis of present genetic parameters.

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Author(s): Carl A. Mohn, Donald E. Riemenschneider, William H. Cromell, L. C. Peterson

Publication: Tree Improvement and Genetics - Lake States Forest Tree Improvement Conference - 1975