University of Alberta Genetic variation in lodgepole pine and interior spruce: adaptation to climate and implications for seed transfer

This thesis investigates genetic variation of two commercially important conifers in western Canada, interior spruce and lodgepole pine. The goals were to quantify genetic diversity and geographic structure, to describe multitrait adaptation to local climates, and to use this information for the development of seed zones for Alberta and British Columbia. The study is based on common garden experiments in growth chambers simulating multiple environments. Genetic differences in phenology, frost hardiness and seedling growth were assessed for approximately 250 seed sources. The results show that 85% of the trait variation was found within populations of both species, while only 15-20% of the among-population variation (or 2-3% of the total variation) could be interpreted as multitrait adaptations to different macroclimatic regions. A key finding of this study is a remarkable degree of genetic diversity in climate-related adaptive traits, implying enough evolutionary capacity to adapt to new environmental conditions. Our results indicate that the current seed zones system can be simplified, especially in Alberta. No more than 20 seedzones for each, lodgepole pine and interior spruce, are required to guide reforestation across Alberta and British Columbia, substantially reducing logistics for seed management.