1. State Plant Breeding Institute, University of Hohenheim, Stuttgart 70593, Germany
2. Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Stuttgart 70593, Germany
3. Key Laboratory of Crop Heterosis and Utilization, Ministry of Education, Key Laboratory of Crop Genetic Improvement, Beijing Municipality, National Maize Improvement Center, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China