1. Department of Plant & Environmental Sciences, Clemson University, Clemson, South Carolina 29634, United States
2. Crop
Production Systems Research Unit, United States Department of Agriculture, Stoneville, Mississippi 38776, United States
3. Natural
Products Utilization Research Unit, United States Department of Agriculture, Oxford, Mississippi 38677, United States
4. Department
of Mathematical Sciences, Clemson University, Clemson, South Carolina 29634, United States