Research Of Characteristics Of Large Grain Germplasm Of Rice

In this paper, grain weight more than 40g a large grain germplasm of rice (31C122,31C125) for the research materials, the ordinary varieties of rice (Jiyujing, Yanda302, Fuyu333) as the control of a large grain of rice germplasm characteristics of grain filling and grain filling synthesis of starch-related changes of enzyme activities. The results are as follows: 1. Grain filling characteristics of large grain germplasm of rice(1) Grain filling rate of differently-positioned grains for large grain germplasm of rice were higher than ordinary ones. The time of the maximum grain filling rate of superior grains for large seed varieties was later compare with superior ones of ordinary ones. The maximum grain filling rate appeared about 24 to 27 days after flowering for large grain germplasm of rice, which fastigium was put off compare with ordinary ones (15 to 23 days). Grain filling rate curves of large grain germplasm of rice were right, ordinary one were left. Large grain germplasm of rice had great initial grain filling potential and the maximum and mean grain filling rate more than twice compare with ordinary ones. The active grain filling period was shorter than ordinary ones. Asynchronous grain-filling were found for 31C122, Jiyujing and Yanda302,31C125 was typical synchronous type.(2) A, GRm, Va and Wpoi were positive correlated with 1000-grain weight 1000-plump grain weight and length of panicle. A, GRm, Va and Wpoi were negative correlated with filled grains density. Regression analysis showed that the main factor affected grain weight was filling rate. 2. Changes of enzyme activities of synthesis of starch for large grain germplasm of rice in grain filling stage(1) Changes of enzyme activities of synthesis of starch for differently-positioned grains.The time of maximum activities of enzyme synthesis of starch for superior grains was earlier than inferior ones. Enzyme activities of SS and SPS of superior grains were higher than inferior ones in early filling stage and lower than inferior ones in last filling stage. AGP enzyme activity of superior grains was higher than that inferior ones in filling stage. SSS enzyme activities of superior grains were higher than inferior ones in last filling stage.Q enzyme activity of superior grains was higher than inferior ones in early filling stage.(2) Changes of enzyme activities of synthesis of starch for large grain germplasm of rice.SS, SPS, SSS and Q activity of superior grains of large grain germplasm was lower than ordinary ones in early filling stage. There were not laws in five enzyme activities of inferior ones for the tested materials. The time of maximum activities of SS and Q of superior grains of large grain germplasm was later than ordinary ones. The time of maximum activities of AGP and SSS of superior grains of large grain germplasm was earlier than ordinary ones. The time of maximum activities of SPS of superior grains of the tested materials was 10 to 15 days after flowering. The time of maximum activities of SS of inferior grains of large grain germplasm was later than ordinary ones. The time of maximum activities of AGP, SSS and Q of inferior ones of the tested materials was 15 to 25 days after flowering and SPS was 30 to 35 days after flowering.(3) Changes of total sugar and starch contents for large grain germplasm of rice,sugar contents of inferior grains was higher than superior grains in all tested materials, sugar contents of large seeds was lower than ordinary ones; Starch contents of superior grains was higher than inferior grains, starch contents of ordinary ones was higher than large seeds, amylose contents of large seeds was lower than ordinary ones(4) Relation of between enzyme activities of synthesis of starch and starchAverage and maximum activities of AGP, SSS, Q and SS were positive correlated or highly significant positive correlated with starch contents. Average and maximum activities of AGP, SSS, SS and Q were positive correlated or significant positive correlated with average rate of accumulations of starch. Average and maximum activities of SPS were negative correlated with starch contents as well as average rate of accumulations of starch.