1 Department of Forestry, Beihua University, 3999 East Binjiang Road, Fengman District, Jilin 132013, China.
2 State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 51 Hexing Road, Harbin 150040, China.
3 Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, 840 Main Campus Drive, Raleigh, NC 27695, USA.