Associate Director, University of Florida Genetics Institute, University of Florida, Gainesville, FL (2005-present).
Professor, Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, FL (1997-present)
Associate Professor, Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, FL (1991-1997).
Assistant Professor, Vegetable Crops Dept., University of Florida, Gainesville, FL (1986-1991).
Postdoctoral Research Associate, Vegetable Crops Dept., University of Florida, Gainesville, FL (1985-1986), with L. Curtis Hannah (maize genetics and molecular biology of sucrose metabolism)