Trichoplusia ni herbivory pressure on crop domestication: Exploring the yield-defense trade-offs in Brassica rapa

Crop breeding techniques typically emphasize high product yield and are often performed in controlled environments lacking natural predators. This reduces selective pressures on plant defense systems, resulting in a need for constant pesticide use. Developing crop breeding programs that simultaneously optimize yield and defense would increase agricultural success and food supply. This study explores the resource-allocation trade-off hypothesis using Brassica rapa oilseed plants and Trichoplusia ni caterpillars. In this ongoing study, we selectively bred B. rapa for high seed oil yield while under herbivore pressure by Trichoplusia ni. Early data from the first five generations indicated that plants subjected to herbivory may produce seeds with lower oil content than those without herbivory. Analysis of direct and indirect plant defenses and herbivore resistance traits is ongoing. The results from this project will benefit growers by providing new information to develop crops that will combine high yield with improved herbivore resistance. Long-term this study will help improve breeding strategies to maximize yield without compromising resistance and improve options for organic and no-spray growers.