Abstract: Based on the daily meteorological data of 25 meteorological stations from 1961 to 2006 and phonological and biomass data of double rice of 31 agro-meteorological stations from 1981 to 2006 in Hunan and Jiangxi Province,the ORYZA 2000 model was calibrated and validated.The rice production areas in two provinces were divided into seven areas according to the phonological parameters,climate,land use form and rice genetic characteristics.The localized ORYZA 2000 model was run at regional scale.The potential climate productivity of double rice were calculated in 25 agro-meteorological stations from 1961 to 2006 based on the simulated results of early rice and late rice.The characteristics of the spatial distribution and temporal variation were analyzed.The results showed that the potential climate productivity was relative higher in the east and central Jiangxi Province and central Hunan Province.The regions with lower potential climate productivity were located in the north and the south of Hunan and the northeast and the south Jiangxi.In regard to the temporal variation,the potential climate productivity in 18 stations among 25 stations decreased with time gradually,which reduce from 22 to 86 kg/ha each year.The preliminary analysis showed that the reduction of the potential climate productivity was due to shorter growing period,less radiation and increment of accumulated temperature during the growing period.The less radiation resulted in less photosynthesis substance,while the higher temperature led to stress on rice growing,or shorter growing period of rice.

Key words: ORYZA 2000, ORYZA 2000, Double cropping rice in Hunan and Jiangxi, Potential climate productivity, Spatial distribution and temporal variation