Population Genetics of Populus trichocarpa for Targeted Breeding as a Biofuel Crop

Populus trichocarpa (poplar) is a woody species native to the western U.S. and Canada. As a fast-growing crop, it has been under investigation by the Department of Energy as a resource for liquid biofuel production. Having recently expanded the collection of poplar whole-genome sequences so that it spans the entire natural species range, we have the novel opportunity to study adaptive responses across this range. This work starts with an initial proof of concept study in a well-studied portion of the species range that has complete whole-genome sequences and RNA expression. The completeness of these data allow robust validation of the methods used. Having demonstrated our methods, we expand our study to include the unstudied portion's of poplar's range. Using these data, we map nine novel genomic loci as regulators of climactic response. This comes with the implication that poplar's response to abiotic stressors are not a genome-wide phenomenon, but restricted to a small number of key regulators. This novel finding has massive implications on the feasibility of engineering poplar for climate resiliency, and enhanced biomass production. The final study leverages this understanding to investigate the predictive capacity that resides in the genome for these climate and geo-spatial traits. Initial results highlight promising avenues for future investigations using our association mapping targets. We are also able to use this prediction architecture to identify mislabeled genotypes, and subsequently correct their labels.