1. State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, Lanzhou 730000, China
2. Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Lanzhou 730000, China
3. Engineering Research Center of Grassland Industry, Ministry of Education, Lanzhou 730000, China
4. College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China
5. College of Agriculture, Nanjing Agricultural University, Nanjing 210000, China