Quantitative genetics and QTL mapping of growth and wood quality traits in coastal Douglas-fir

Coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var menziesii) is one of the most commercially important tree species on the west coast of British Columbia and the United States due largely to its superior wood quality. Several growth and wood quality traits, including height, diameter, volume, earlywood, latewood and average density, latewood proportion, fibre length and coarseness, and complete cell wall chemistry, were measured for 600, 26 year old Douglas-fir trees from 15 full-sib families located on four sites in southwestern British Columbia. Bud samples were collected and DNA isolated for molecular marker analysis. Family data were used to calculate broad-sense heritabilities, and genetic, phenotypic and family mean correlations for all traits. Amplified fragment length polymorphism (AFLP) data from eight families was used to generate a linkage map employing a joint likelihood function, which contained 19 linkage groups with 120 markers spanning 938.6cM of the Douglas-fir genome. A QTL map for commercially important traits was created using a combination of interval mapping by sib-pair analysis and single locus analysis by analysis of variance. Fibre properties have the lowest heritability (0.10 - 0.18), while glucose content has the highest heritability (0.98). Growth traits are under moderate genetic control (0.23 - 0.30) as is microfibril angle (0.20). For growth ring traits, earlywood density and average density have moderately high heritabilities (0.54 and 0.47, respectively) followed by latewood proportion (0.30) and latewood density (0.21). Average density is influenced primarily by the proportion of latewood (0.85) and earlywood density (0.74). Growth traits, which are important components of tree improvement programs, are generally positively correlated with fibre traits, microfibril angle and lignin content, but negatively correlated with density and cell wall carbohydrate content. Twenty-two QTLs were detected for compound traits that explained between 3.6% and 17.7% of the phenotypic variation. An additional 78 individual ring density QTLs were identified which form 11 QTL clusters and 11 independent QTLs. The resulting map should serve as a valuable scaffold for future metabolite QTL mapping and comparative genomic projects.Forestry, Faculty ofGraduat

Growth and survival of lodgepole pine and Scots pine after 25 years in a reciprocal transplant experiment in Canada and Sweden

Lodgepole pine is native to western North America, but it is also planted as a fast-growing alternative to Scots pine in Sweden. The production of these two species, when grown as native and as exotic species, was compared in a transcontinental two-species provenance experiment. The tests were planted in 1986 on five sites in northwestern Canada and two sites in Sweden, and included full-sib families, half-sib families, seed orchard collections and natural stand seed collections of both species. After 25 years, lodgepole pine produced 48% more volume (m(3)ha(-1)) and had 27% higher survival than Scots pine at one Swedish site, and had similar volume production and survival at a second. In the five Canadian sites, Scots pine produced on average 22% more volume than lodgepole pine. The variation between sites was, however, large. This higher volume of Scots pine in Canada could be due to higher survival (+28%) and less frequent damage; but higher top height for lodgepole pine in Canada indicated higher potential productivity. The results indicate that an exotic species may produce more than the native species, possibly thanks to higher survival, but it is also possible to increase production with successful population selection of the native species

Climatic drivers of genotype-environment interactions in lodgepole pine based on multi-environment trial data and a factor analytic model of additive covariance

The optimum deployment of select material from tree breeding programs is affected by the presence of genotype-environment (GxE) interactions and further complicated by future climate change. Here, we analyzed tree height data from 28 progeny test sites in a multi-environment trial (MET) dataset for two testing cycles of the lodgepole pine (Pinus contorta Douglas ex Loudon) breeding program in British Columbia to characterize one approach to investigating the climatic variables influencing GxE, and the potential impacts of climate change. Linear mixed model analysis was conducted using an approximate reduced animal model with a factor analytic (FA) variance model to estimate the complex additive (co)variance structure. Test sites were grouped according to patterns of GxE and climate modelling was employed to project historical and future deployment zones for each group. Based on these findings, it appears that breeding groups with historically wide deployment zones from northern environments will become less important as the climate warms, and therefore investment should be directed toward southern breeding groups which will be useful across a very wide geographic range in the near to mid-term future.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author