Genetic and phenotypic correlations among volume, wood specific gravity and foliar traits in white spruce (Picea glauca (Moench) Voss)

Abstract

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.

Effects of artificial warming during quiescence on budbreak and growth of white spruce, Picea glauca

“…Two sources represent wild-collected seed bulked from each of two different seed zones originating from approximately 100 kilometers north of the study site, because much of the white spruce planted originates from, or is planted into, forests that are north of the study site. Open-pollinated seed from five maternal genotypes, selected for having above-average height growth at a D r a f t progeny test (Pike & Montgomery 2015), was collected from a clonal seed orchard owned by UPM Blandin in Grand Rapids, Minnesota at: 47°15' N Lat and 93°29' W Long, MAT= 3.9°C, MAP= 627.4 mm. The combination of wild and selected seed sources was chosen to represent the diversity of growth that is a hallmark of white spruce, but differences between wild and selected sources are not the focus of this study.…”