With an agriculture PhD, you could position yourself for careers in high levels, such as agriculture professors, CEOs or investors. Compared to a masters program in the field, this degree level focuses more on specializations in economics.
University of Missouri - Columbia
M.S. degree available with 24 hours of course work and a thesis or 30 hours of coursework and a technical paper. Ph.D. degree available with emphasis in one of the three research thrust areas listed above.