Effect Of Temperature And Light Condition On Grain-filling And Rice Quality

Materials used were Diantun502and E-you 540 (medium-maturing irufica rice) Hexi39 and hexi22-2 (medium-maturing japonica rice), Fengyouxiangzhan (a hybrid rice. On different sowing dates and cultivated location.the panicle m"2 .characteristic of grain filling, and the relationship between temperature and sunshine and rice quality were investigated.The obtained results were as follows.(1) During the grain filling period.the filling velocity of superior grain might be higher than that of inferior grain;the velocity of japonica rice had a bigger value than that of indica rice.the daily mean temperature during 15d after heading was a important factor of grain filling.we recognized that higher temperature increased R0( filling initial power) of grain and advanced the inflexion time of filling matter curve and filling veolcity .the result showed that synchronization and asynchronism filling was not only the character of varieties ,but also influenced by meteorologic factors of grain filling.(2) Considering the amylose content(AC),the correlation between AC and the daily mean temperature during grain filling period was significant with quadratic equation. Moreover ,AC correlated significantly with the days of flowering with conic or cubic polynomial model respectively. Besides during the 16 days after heading , the increased velocity of AC surpassed that of grain weight and vice versa in the later filling period. This demostrated that AC obtainedfromthe initial of matter accumulation.however .Amylopectin was accumulated mainly during the later filling stage.(3) Quality traits of rice revealed a correlation with temperature and illumination respectively during grain filling stage. There was a negative correlation between daily mean temperature and milling quality ,such as browed rice rate .milled rice rate.and head milled rice.meanwhile, the daily mean temperature positively correlated with chalky degree.chalkiness rate,GC(gelatinization consistency)and protein content respectively.In addition,the chalky degree and chalkiness ratio increased with daily mean illumination increased during grain filling period. Furthermore.the browed rice rate and milled rice rate of Hexi39,japonica rice, significantly increased with sunshine hour, the relationship was calculated by:y1=80.738368+0.501887x1,y2=69.739348+0.882326x2.(4) Analysed the relationship between rice quality and the character of grain filling,the mainly results indicated that the rice milling quality decreased with dry matter accumulation in curve inflexion and chalkiness increased while hardness of GC increased.the same time ,the velocity of grain filling increased as well as chalky degree and chalkiness . rice quality was influenced reasonably by the days of inferior grain filling ,rice quality was improved with the longer duration of inferior grain filling.(5) To sum up.with different genotype of rice as materials,the rice quality of japonica rice was influenced no significantly than indica rice by environmental.Results of these studies suggested that rice quality would beincreased if we regulated sowing dates and improved the meteorologic factors during grain filling...