Canadian Forest Service Publications

Distribution of genetic variation in five coppicing growth traits among and within natural populations of seven North American willow (Salix) species. 2016. Mosseler, A.; Major, J.E.; Ostaff, D.P. Canadian Journal of Forest Research 47: 36–46.

Year: 2016

Available from: Atlantic Forestry Centre

Catalog ID: 37378

Language: English

CFS Availability: PDF (download)

Abstract

Genetic variation and population structure in biomass yield and coppice growth traits were assessed in seven native North American willow species (Salix amygdaloides (AMY), Salix bebbiana (BEB), Salix discolor (DIS), Salix eriocephala (ERI), Salix humilis (HUM), Salix interior (INT), and Salix nigra (NIG)) established together in common-garden field tests on two sites. Differences in biomass yield, coppice stem number, and average single-stem mass were significant at the site, species, population, and genotype (clonal) levels. There were also species × site interactions. Analyses of variance components for these traits showed that only 3%–5% of the total variation in these traits was due to site differences, whereas genetic variation at the species, population, and genotype levels accounted for approximately 10%–39%, 5%–13%, and 12%–23%, respectively. Populations were a significant source of variation in some willow species (e.g., AMY, DIS, ERI, and INT) but not in other species. Tree willows were less prolific in stem sprout production than shrub willows, and ERI coppices produced by far the highest number of stem sprouts per coppice. This multispecies investigation demonstrated strong species and clonal differences, but variation among populations within a species, although significant, was relatively small, indicating that major growth and yield gains can be made through proper species selection and clonal selection within local populations.

Plain Language Summary

There is growing interest in North America in understanding variation patterns in native willows (Salix spp.) both as potential sources of fast-growing woody biomass and for rapid reclamation and restoration of highly disturbed areas affected by various industrial activities. Canada has 76 native willows, yet very little is known about genetic variation among and within North American willows, despite their ecological importance as pioneer colonizers and invaders of disturbed sites. Genetic variation and population structure in biomass yield and coppice growth traits were assessed in seven native willows. In a comparison of growth on the stone-free, sandy-loam soil of a tree nursery vs. the rocky shale rock overburden of a former coal mine site, differences in biomass yield, coppice stem number, and average single-stem mass were significant at the site, species, population, and genotype levels, but also showed a significant species x site interaction. Analyses of variance components for these traits showed that approximately 3–5% of the total variation in these traits was due to site differences, whereas genetic variation at the species, population (within species), and clonal (genotype) levels accounted for approximately 10–39%, 5–13%, and 12–23%, respectively. Populations were a significant source of variation in some willow species, but not in others. The tree willows were less prolific in stem sprout production than shrub willows. This multispecies investigation demonstrated strong species and clonal effects on growth. Variation among different populations within a species—albeit significant—was relatively small, indicating that major growth and yield gains can be made through proper species and clonal selection.

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