| Two indica rice cultivars, Jiazhao 935 with good grain quality and Zhe 733 with medium grain quality, were widely planted common paddy rice in Zhejiang Province with similar yield potential, resistance to pests and diseases and times of maturity and obvious differences in genetic background. These two cultivars were grown at ten diverse ecological sites in Zhejiang Province to determine the relationships between rice qualities and and climatic factors during the grain filling stage. Rice quality traits included brown rice rate (BRR), milled rice rate (MRR), head milled rice rate (HMR), length (L) and ratio of length to thickness of brown rice (RLT), transparency (T), rate and degree of chalkiness (CR and C), gelatinization temperature (GT), gel consistency (GC), amylose content (AC) and protein content (PC), Climatic factors were daily mean air temperature, daily mean maximum air temperature, daily mean minimum air temperature, daily mean solar radiation and daily mean precipitation. Among ten experimental sites with different latitude, Changnan, Wenlin, Nibo, Shaoxing and Jiashan belong to the littoral plain regions, and Taishun, Shuichang, Kaihua, Lingan and Anji belong to inland hill regions. The experiments were conducted in two successive years, 1999 and 2000, with diverse climatic conditions. Compared to the mean value of multi-year data, 1999 showed markedly lower air temperature, increased precipitation and decreased solar radiation, however, 2000 showed higher air temperature and similar precipitation and radiation. A mixed linear model including the genotype, year and location effects and the interaction effects of year by location, genotype by year and genotype by location was employed to unbiasedly estimate variance component of random effects of each trait and correlation coefficients of each random effect among r ice q uality t raits(Rao, 1971; Zhu, 1989, 1992), t he v alues o f the r andom effects were predicated unbiasedly using the adjusted unbiased prediction(AUP, Zhu, 1993). Lastly, the effects of year, location, genotype and their interactions on the variation of grain quality traits for the early indica rice in Zhejiang were comprehensively analyzed. The main results were as followed:The results showed that, w ithin t he grain quality traits, PC was significantly affected by year, BRR, HMR, RLT and T was mainly affected by the effects related to location, and MRR, L, CR, C, GC, GT and AC were controlled primarily by genotype and its interaction with other factors. Within the climatic factors during the grain filing stage for the early rice, daily mean air temperature, daily mean maximum air temperature and daily mean solar radiation were mainly affected by the year factor, while the variations of daily mean minimum air temperature anddaily mean precipitation resulted mainly from the interactions between year and location.It was found that there were more sensitive responses of BRR, C and PC to the variation of climatic condition between different years, while relative smaller responses for the other quality traits. In this study, no significant differences among the effects of ten locations existed on BRR, MRR, L, CR, GC, RLT, GT and AC, respectively, implying locations have stable effects on these quality traits. In terms of stability of location effects, HMR, RLT and T showed lower and C showed lowest stability, respectively. There were no significances for the predicted values of interaction effects between year and location for other quality traits, except PC, AC, GT and CR. No significance of effects of genotype by year on BRR, HMR, L, RLT, C, CR, GT and PC and predicted values of Jiazhao 935 for T and Zho 733 for GC under different years were found, on the contrary, the BRR of the Jiazhao 935 and the GC of the Zhe 733 were significantly affected by the effects of genotype under different years. Meanwhile, it was also found that there were no significant differences in the effects of genotype by location interaction on BRR, HMR, L, T and PC, indicating good stability of effe...
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