1. Clemson University, Edisto Research and Education Center, 64 Research Road, Blackville, South Carolina 29817. Corresponding author, E-mail:
2. University of Georgia, 2360 Rainwater Road, Tifton, Georgia 31793.
3. Clemson University, Pee Dee Research and Education Center, 2200 E. Pocket Road, Florence, South Carolina 29506.