Abstract:

【Objective】 This study was conducted to investigate the relationship between leaf position on the stem of rice cultivar and effective accumulated temperature and to describe the progress of leaf appearance on main stem of rice. 【Method】 Sixteen rice cultivars were used in this experiment. They were planted with different sowing dates in Nanjing, Jiangsu and Lijiang, Yunnan. The relationship between leaf position on the stem of cultivar and effective accumulated temperature was observed. 【Result】 The results indicated that the leaf within one stem appeared more later it would need more effective accumulated temperature. Moreover, there were two turning points during rice growth period. One appeared when leaf number was 3 and the other one emerged while leaf number equaled N-n-2. Therefore, the piecewise function was used to describe the progress of leaf appearance on main stem of rice. Data collected from two regions were used to validate the model. The RMSE between simulated values and measured values were less than 0.1. 【Conclusion】 This study suggested that the model had good forecast ability and practicability for leaf appearance.

Key words: rice, leaf age, effective accumulated temperature, simulation model