1. College of Agronomy, State Key Laboratory of Wheat and Maize Crop Science Henan Agricultural University Zhengzhou 450002 China
2. College of Life Sciences Henan Agricultural University Zhengzhou 450002 China
3. State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, College of Agronomy and Biotechnology China Agricultural University Beijing 100193 China
4. International Maize and Wheat Improvement Center (CIMMYT), El Batan Texcoco 56237 Mexico