1. Dep. of Plant Biology; Univ. of Minnesota; St. Paul MN 55108
2. Dep. of Plant Sciences; North Dakota State Univ.; Fargo ND 58105-5051
3. Dep. of Soil and Crop Sciences; Colorado State Univ.; Ft. Collins CO 80523
4. Crop Genomics and Bioinformatics Center; Nanjing Agricultural University; Jiangsu 210095 China