Abstract: In terms of the data from the Rice Climatic-Ecological Experiment conducted in the Yangtze Valley (1985—1986) , and the meteorological data during the same period, 3 mathematical models for the number of panicles per unit land area, the number of grains per panicle and, tne numoer of filled-grains percentage were built, respectively. The total hours of sunshine duration and the mean temperature during the tillering stage are the most importana meteorological factors for the effective panicle formation. The length in days from emergence to heading and the effective panicle number are important determinants of grain number per panicle. As to the number of filled-grians percentage, the total sunshine duration in hours and the mean maximum and minimum temperature during the period covering 15 days before and 25 days after heading are the determinants. A sink yield model was also developed, based On the following assumpation, i. e. , the 1000-grain weight was considered as one of the stable varirtal characteristics and the empty grains percentage was the limiting factor to the sink yield. This means the formation of partial filled grains percentage relates to the shortage of source yield. A good agreement has been found between the simulated results and the experimental data.

Key words: Simulation Model, Simulation Model, Sink Yield, Yield Component