Date of Graduation


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Stephen DiFazio

Committee Co-Chair

James McGraw

Committee Member

Kevin Barry


In an attempt to enhance the efficiency of biofuel production, research has traditionally focused on wood chemistry in forest trees. Altered wood chemistry has the potential to reduce recalcitrance to carbohydrate extraction and conversion, but may have unintended effects on dormancy. In Populus deltoides (eastern cottonwood), changes in dormancy may inhibit annual growth rates or put the trees at risk for frost damage, compromising benefits of genetic engineering. Genome wide association analysis indicates that multiple polymorphisms in and around the Potri.013G001600.1 gene of unknown function have a strong association with bud set date. This experiment isolated the gene's transcription levels in order to determine the effects of gene expression on bud set dates and secondary branching in P. deltoides. Multiple levels of gene expression were created via RNA interference (RNAi) caused by Agrobacterium mediated transformation. All lines were grown in a growth chamber with controlled lighting and temperatures to induce bud set. Levels of Potri.013G001600.1 gene expression were tested using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). A linear regression of gene expression and bud set date were calculated to determine gene effects. The direct results of this experiment suggest that expression of this gene was not substantially altered by RNAi. Furthermore, there was only weak evidence that levels of expression of this gene are associated with bud dormancy. This study therefore lends little support to the hypothesis that altering genes involved in wood chemistry could cause altered dormancy.