Study On The Effect Of On Yield And Quality Formation Of Japonica Rice Cultivars Planted In Liaoning In Large Acreage

1. Results based on the analyses of quality performance of japonica rice varieties Liaojing 294 and Liaoyan 16 and meteorological data from 2001 and 2005 showed that daily mean temperature was correlated with brown rice rate, chalkiness size and ratio of grain length to width, and negatively with chalkiness degree, grain width, transparency and amylose content. The sun radiation was correlated significantly positively with polished rice rate, head rice rate, chalkiness percentage, transparency and amylose content, but negatively with chalkiness size and brown rice rate. Except that precipitation was correlated less with chalkiness degree and gel consistency, it had much more correlation with other quality traits.2. Taking ten rice cultivars like Shennong 9765 and Liaoyou 267 as entries, the sunlight and temperature effect on yield and quality was studied through sowing by time, and the results showed that sun-shining hours between transplanting and initial heading, accumulated temperature from initial heading and maturity, and accumulated temperature between transplanting and initial heading were correlated closely with biomass, daily dry matter increasing amount and grain weight. Sun-shining hours and range of temperature between transplanting and initial heading, were correlated closely with shriveled grains per panicle, growth period, and full grains per panicle. Illumination at transplanting and accumulated temperature between initial heading and maturity were correlated with protein content, chalkiness grain rate and ratio of grain length to width.3. The results of shading panicle part showed that the decrease of lightness density resulted in the reduction of individual plant yield, biomass, grain weight and kernel setting rate. The dry matter accumulating amount decreased in culms, leaves and panicles. Except grain length and ration of grain length to width, the rice quality traits were significantly affected by illumination. Weak lightness led to reduction of brown rice rate, head rice rate, transparency and amylose content and significant increase in chalky grain rate and protein content.4. High temperature effect on rice was studied at filling stage in green house in pot and the results showed that high temperature was able to increase both kernel setting rate significantly and grain weight. The head rice rate was lowered and the chalky grain rate, chalkiness degree and protein content were increased at high temperature condition. There existed great differences of quality traits among cultivars at high temperature condition.