J. D. Sauerländer's Verlag, Bad Orb

White spruce is highly valued by the forest products industry in North America. Through tree improvement efforts, selected genotypes can exceed wild sources by 30% in volume. Negative correlations between growth and wood specific gravity have been established, but differences in leaf morphology between high and low performing genotypes are less well understood. We sampled five trees from each of 30 families at each of two locations in a 25-year old progeny test in Minnesota. One wood core was collected from each tree to sample wood specific gravity (WSG), along with a branch collected from the upper crown to examine foliar traits. We confirmed negative correlations between stem volume and WSG, but several families combined high wood volume with only small reductions in WSG. Leaf area ratio and specific leaf area were positively, genetically correlated with volume growth but not correlated with WSG. Increased growth rates of selected genotypes may be attributed, in part, to shifts in allocation to leaves and in leaf morphology that may optimize light interception.

Key words: white spruce, genetic correlations, wood specific gravity, specific leaf area, genotype by environment interaction, foliar nitrogen.

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