Date of Thesis

5-7-2014

Thesis Type

Masters Thesis

Degree Type

Master of Science

First Advisor

Elizabeth Capaldi Evans

Abstract

Every year agricultural companies produce new strains of Solanum, the genus that includes species such as tomatoes, potatoes and eggplants. Using artificial selection, the strains are created for disease resistance and hardiness. However, it is unknown if pollinator-attractive traits are inadvertently lost by this process. It has been documented in strawberries that different strains of the same species produce different amounts of volatile organic compounds. The strain that produced the highest quantity of volatile organic compounds attracted the most pollinators under field conditions, and elicited the greatest antennographic response in Red Mason bees (Klatt et al., 2013). Therefore, I asked if bumblebees, one of the main pollinators of Solanum, are differentially attracted to multiple strains of tomatoes, an important cash crop. Of the three strains used in this study, I predicted that bumblebees would be most attracted to the cultivar with the least disease resistance because it was less likely that any attractive traits had been bred out. I tested this hypothesis using an olfactory based Y-maze behavioral apparatus and determined that in a laboratory setting bumblebees were significantly more attracted to Brandywine, the least disease resistant strain, than Mountain Magic, the cultivar with the greatest disease resistance profile. The results were confirmed using both cuttings of the plants and whole plants. From these data it is possible to say that the volatile organic compound profile of Mountain Magic may have been inadvertently modulated by artificial selection towards disease resistance. Therefore, it is necessary to create a larger scale study to determine if this trend is endemic to all artificially selected tomatoes, or localized to these two strains.

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