1. Dep. of Crop Science, Box 7629; North Carolina State Univ.; Raleigh NC 27695-7629
2. USDA-ARS and North Carolina State Univ.; 840 Method Rd. Unit 3 Raleigh NC 27695
3. Dep. of Agronomy and Horticulture; Brigham Young Univ.; 275 WIDB Provo UT 84602
4. USDA-ARS and North Carolina State Univ.; 1419 Gardner Hall Raleigh NC 27695