1. Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin 150030, P. R. China; and Department of Plant Pathology, University of Georgia, Tifton 31794
2. Agricultural College, Northeast Agricultural University, Harbin 150030, P. R. China
3. Crop Genetics Research Unit, USDA–ARS, Stoneville, MS 38776
4. Department of Plant Pathology, University of Georgia, Tifton 31794.