1. College of Foresty, Guizhou University, Guiyang, China
2. Guizhou Institute of Walnut, Guizhou Academy of Forestry, Guiyang, China
3. State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
4. School of Forestry, Northeast Forestry University, Harbin, China
5. College of Life Science, Northeast Forestry University, Harbin, China