This study was carried out to develop rice growth model when cultivate early maturing rice cultivar, Unkwangbyeo, in Honam plain area. To confirm leaf emergence rate and variation of heading date, we transplanted 15 day and 30 day old seedling on May 1, May 15, May 31, June 15, June 30, respectively.
The growth duration between transplanting and completion of leaf emergence on main culm were 50.1~78.3 days in 2007 and 47.5~74.7 days in 2008. Growth duration diminished gradually as transplanting time delayed, but the difference of growth duration by transplanting time were more bigger than that of seedling day. The emerged leaf number after transplanting on main culm were 8.9~10.9 in 2007 and 8.4~10.9, respectively. The emerged leaf number diminished as transplanting time delayed, but the difference of emerged leaf number by transplanting time were more bigger than that of seedling day. The cumulative temperature between transplanting and completion of leaf emergence on main culm were 1,281~1,650℃ in 2007 and 1216~1560℃ in 2008. The solar radiation between transplanting time and completion of leaf emergence on main culm were 709~1,245MJ/㎡ in 2007 and 722~1,220 MJ/㎡ in 2008. The sunshine hours between transplanting time and completion of leaf emergence on main culm 234~433 hours and 238~431 hours, respectively.

• Jae-Kwon Ko(Div. of Rice Breeding and Physiology, Honam Agricultural Research Institute, RDA)
• Young-Doo Kim(Div. of Rice Breeding and Physiology, Honam Agricultural Research Institute, RDA)
• Young-Joon Mo(Div. of Rice Breeding and Physiology, Honam Agricultural Research Institute, RDA)
• Nam-Hyun Back(Div. of Rice Breeding and Physiology, Honam Agricultural Research Institute, RDA)
• Hong-Kyu Park(Div. of Rice Breeding and Physiology, Honam Agricultural Research Institute, RDA)
• Weon-Young Choi(Div. of Rice Breeding and Physiology, Honam Agricultural Research Institute, RDA)
• Bon-Il Ku(Div. of Rice Breeding and Physiology, Honam Agricultural Research Institute, RDA) Corresponding Author