Studies on the Difference of Yield Components Characteristics Between Indica and Japonica Super Rice

In order to reveal the difference of yield components characteristics between indica and japonica super rice, Field experiments were conducted by using five main representative super hybrid indica combinations and five conventional japonica super rice varieties in rice-wheat cropping regions. Grain yield and its components,dynamics of population stems and tillers,panicle characteristics and grain-filling properties were analyzed systematically. The results indicated that,grain yield,panicle numbers,total spikelets,setting percentage,storage capacity,total filling,ratio of productive tillers,grain density,ratio of No. of branches of primary branches to No. of branches of secondary branches, ratio of total grains of primary branches to total grains of secondary branches,No. of branches of primary branches per panicle,grains per branch of primary branches,total grains of primary branches per panicle,seed-setting rate of primary branches,seed-setting rate of secondary branches,the final weight of a kernel,the time reaching the maximum grainfilling rate,the weight of a kernel at the time of maximum grain-filling rate,active grain-filling period and effective grain-filling period of japonica rice were higher than indica rice,while spikelets per panicle,1000- grain weight, panicle length,grain weight per panicle,No. of branches of secondary branches per panicle,grains per branch of secondary branches,total grains of secondary branches per panicle,initial grain-filling potential,maximum grain-filling rate and mean grain-filling rate followed an opposite tendency accordingly. However,no significant trend was observed for the ratio of the weight of a kernel at the time of maximum grain-filling rate to the final weight of a kernel between indica and japonica rice. Although the grain-filling processes of indica and japonica super rice were all asynchronous types,the phenomenon of two-stage grain-filling was more illustrious in indica rice. The grain-filling of indica rice started quickly and accumulated rapidly with short duration,declined fast in the end. The grain filling at the early, middle and late stage for inferior grains of japonica rice were higher than indica rice with the increasing range of 0. 73%, 2. 59%,3. 43%,respectively,which suggested that the advantages of japonica rice would go larger and larger with the advancement of grain-filling. The stable-increasing-stable-decreasing tendency of population stems and tillers,multipanicles,rational panicle structure,high seed-setting rate,stable and long duration grain-filling and high quality grainfilling for the inferior grains at the later period of grain-filling were the key points of enlarging sink,promoting the enrichment,stable yield and high yield of japonica rice.