Abstract: With the application of mechanistic model (RICAM 1.3,RIce growth Calendar Model),this paper simulated the rice development and its yield formation under different climatic conditions at multi-locations of Asia.A threestage Beta model (3s-Beta) was developed to predict the flowering stage of rice and to describe its three successive phases of photo-thermal response,i.e.,basic vegetative phase,photoperiod-sensitive phase,and post photoperiod-sensitive phase.The 1980～1989 multi-location data of Morioka (Japan,39°43′N),Nanchang (China,28°36′N) and Los Banos (Philippines,14°11′N) were used to verify the suitability of the model in studying eco-system change.Comparisons of simulated results with observed data showed that this model could generally predict the eco-physiological processes of rice,and performed very well over a wide range of environments.

Key words: Rice germplasm, Brnyardgrass, Allelopathy