<p>Many of the better Botany programs are at the large public universities that have a College of Agriculture. Some of those departments will be focused on food plants. You also should run some searches for programs in Ethnobotany which is the study of how people use plants. You would get to go on research expeditions to remote locations, hang out with the local people, and talk with them about what plants they use for food and medicine. These programs might be inside an Anthropology department, rather than inside a Botany department.</p>