Abstract
The concept of developmental index (DVI) is used to estimate crop phenology from climatic conditions. The DVI model comprises a summation of polynomial expressions describing the developmental rates (DVR) that are individually functions of climatic parameters such as daily mean air temperature and photoperiod. Using the defined polynomial DVR functions, the DVI model can be solved using linear algebra by finding the linear least squares solutions. This method is unique and has high reliability. Using the results of field experiments, both the DVR of rice plants for period from emergence to heading and the DVR of cabbage from planting to harvest were estimated. These results are consistent with cultivation guides. These findings can be used to develop ways to analyze phenological data based on climatic parameters.
