Studies on Morphological Characters of the Super Rice Varieties with Different Plant and Panicle Types

The result of studies on the morphological character, rate of the upper three leaves contribution to grains and analysis of grain filling characteristics of Super Rice varieties with different plant and panicle types indicated that: 1. The response to nitrogen supply and density of transplants varied with different plant and panicle types, but the growth curves of all varieties fitted to formula: Y=b1X+b2X2. Under high fertility and high plant density,eaf area of the semi-erect type varieties increased rapidly in the early season and reduced slowly in the late season. So the LAI was high in the heading stage and the light extinction coefficient(K) of canopy was small. The average leaf angle was less than other type of varieties. The light regime in lower parts of canopy was improved,so total effective leaf area increased and yield raised. 2. The LAI was significantly positively correlated with the mass growth and the yield was positively correlated with the growth in early season. 3. The contribution rate of upper three leaves to grain varied with different plant and panicle types.In semi-erect panicle varieties, the third leaf contribution rate was the highest an the contribution rate of second leaf and flag leaf was similar. In curved panicle type varieties, the contribution rate of flag leaf was the highest,whereas that of second and third leaf was smaller, Although contribution rate of the third leaf in erect panicle varieties was the highest, the contribution of the second and third leaf is less than that in semi-erect type varieties. 4. Significant correlation was observed between the number of the large vascular bundles in neck-panicle and grain numbers per panicle. The number of the large vascular bundles in neck-panicle was positively correlated with nitrogen application. 5. The curvature of panicle neck was significantly positively correlated with length, length-width ratio and angle of flag leaf, but it negatively correlated with the number of vascular bundle.