Effects of nutrient limitation and competition on aspen (Populus tremuloides): Investigating genotype x environment interactions, susceptibility to pathogen attack, and insect herbivore performance
An imminent challenge facing society is how to meet the demands of both food production and energy security in a changing environment. Crop production for biofuels competes with production for food because of limited availability of water and arable land. To mitigate this conflict, biofuel feedstock production is increasingly focused on marginal lands with both low fertility and intense competition with herbaceous plant species. Moreover, insect herbivores and pathogens can severely damage plantation-grown plants. Thus, the development of biofuel crop genotypes that both grow well under environmental constraints and are not compromised against insects and pathogens is critical.
Populus species have arisen as the premier woody biofuel feedstock in the U.S.A., and trembling aspen (Populus tremuloides), an important foundation species in natural ecosystems, is the most widely distributed and genetically diverse. Despite the fact that aspen can grow in a variety of locations, growth and performance are strongly limited by soil nutrient availability and competition with weeds, as well as herbivory by insect defoliators and pathogen damage. Therefore, I am investigating the independent and interactive effects of genotypic and environmental variation on tree growth, resistance, susceptibility to pathogens, and insect herbivore performance.