1. Dep.of Plant Sciences Univ. of Tennessee 112 Plant Biotechnology Building Knoxville TN 37996‐4500 USA
2. USDA‐ARS Western Regional Research Center 800 Buchanan Street Albany CA 94710 USA
3. Current address: USDA–ARS Crop Improvement and Protection Research Unit 1636 E Alisal Street Salinas CA 93906 USA
4. Current address: Division of Agricultural Sciences and Natural Resources Oklahoma State Univ. 139 Agricultural Hall Stillwater OK 74078 USA