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