1. Northwest A&F University College of Forestry, , Yangling, Shaanxi 712100, China
2. College of Life Sciences, Northwest University Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, , Xi’an, Shaanxi 710069, China
3. Xi’an Botanical Garden of Shaanxi Province , Xi’an, Shaanxi 710061, China
4. Purdue University USDA Forest Service Hardwood Tree Improvement and Regeneration Center (HTIRC), Department of Forestry and Natural Resources, , 715 West State Street, West Lafayette, Indiana, 47907, USA