We aim to combine phenotypic, genotypic, and environmental data to gain insights into the genetic basis of cold adapted traits in coastal Douglas Fir (Pseudotsuga menziesii var. menziesii). Temperate and boreal trees are not predicted to be able to counteract climate change solely through migration, plasticity and adaptation. Trees show strong adaptation to their local environment and climate change will change the traits that are adaptive in their respective location. Specifically, climate change will bring warming and more extreme frost events. Warming could delay the onset of cold hardening in trees, which would make them more vulnerable to frost damage during cold spells brought on by climate change. To inform strategies to combat climate change (such as seed transfer zones or assisted migration), conservation biologists need a thorough understanding of the genetics underlying natural variation in fitness traits. We took seeds from random trees throughout Oregon and Washington. For genotyping, we pooled DNA from 10 megagametophytes from each tree to infer the maternal genotype. For phenotype data, we grew seeds in a common garden and measured traits related to cold-hardiness. To get environmental data, we used the ClimateWNA database and locations of maternal trees.
Results/Conclusions
Results of the population structure analysis showed that two distinct groups exist within our study zone; one existing in Southern Oregon (type 2), with the other more dominant type throughout the rest of the sampled range, up to the Canadian border (type 1). The two types hybridize, and we also found a small number of hybrids in Southern Oregon. This agrees with a previous study using mitochondrial DNA that found two distinct genetic groups and can probably be explained by migration patterns out of refugia after the last glacial maximum. The hybrids are all more closely related to type 1 than type 2, suggesting asymmetric gene flow from type 1 to type 2. We will perform a GWAS using phenotypes from the common garden and combine this information with genotype-environment associations using environmental data from the Climate WNA database. We expect to find associations between markers, traits, and environments and be able to identify the exact genes involved in the differences because our SNPs are gene-based. This will give us an understanding about which genes are involved with adaptation to cold hardiness and in which populations these genes/traits exist in.