1. Forest Tree Breeding Center, Forestry and Forest Products Research Institute (FFPRI), 3809-1 Ishi, Juo, Hitachi, Ibaraki 319-1301, Japan
2. Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Higashiku, Fukuoka , 812-8581, Japan
3. FFPRI, 1 Matsunosato, Tsukuba, Ibaraki , 305-8687, Japan
4. 92-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate , 020- 0123, Japan