1. Dep. of Crop and Soil Sciences North Carolina State Univ. Raleigh NC 27695 USA
2. USDA and Dep. of Crop and Soil Sciences North Carolina State Univ. Raleigh NC 27695 USA
3. Dep. of Crop and Soil Sciences Univ. of Georgia Tifton Campus Tifton GA 31793 USA
4. Dep. of Horticulture and Landscape Architecture Purdue Univ. West Lafayette IN 47907 USA
5. Dep. of Statistics North Carolina State Univ. Raleigh NC 27695 USA