抄録
The heading dates of photoperiod-sensitive rice plants under natural daylength were investigated in this present study. Six cultivars of rice were sown at two-week intervals over one year period in a greenhouse and maintained under constant temperature. Rice plants sown between August and February were consistent in the number of days required from emergence to heading, while those sown between March and July required more time.
Our model is based on accumulated water temperatures from emergence to heading under short daylength conditions, and can be transformed into the developmental index (DVI). The developmental index is the sum of the developmental rates (DVR) from the emergence day, and is 1 on the heading day. The developmental rate was calculated using non-parametric methods.
