1. Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Inner Mongolia Research Centre for Prataculture, Chinese Academy of Sciences, Beijing 100093, China
4. Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
5. Institute of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun, Jilin 130124, China
6. State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
7. Department of Plant Genetics and Breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
8. Forage Crop Research Institute, Japan Grassland Agricultural and Forage Seed Association, Nasushiobara, Tochigi 329-2742, Japan