1. College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China
2. Institute for Improvement of Forest Genetic Resources and Product Development, Hanoi , Vietnam
3. Institute of Forest Tree Improvement and Biotechnology, Vietnamese Academy of Forest Sciences, Tu Liem, Hanoi , Vietnam
4. CSIRO Plant Industry, GPO Box 1600, ACT 2601, Canberra , Australia