1. State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
2. Department of Crop Science, College of Agriculture & Life Sciences, Chungnam National University, Daejeon 305-764, Republic of Korea
3. Division of Bioresource Technology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea