The Physiological and Biochemical Differences of Grain Quality Formation in Japonica Cultivars with Different Panicle Types

The dry matter accumulations of grain, enzyme activities, chlorophyll contents and grain quality traits of different panicle-type cultivars planted in four N-fertilizer levels were examined. The results showed as follows: The grain dry matter accumulations for different panicle type cultivars were not the same, for erect-panicle japonica cultivars, GR_0 and the rate of grain filling were low during early grain filling period because of the large number of grains per panicle and the high density of grain, but the rate of grain filling was higher during late grain-filling period, the difference of the grain filling between the upper and low part in one panicle was obviously found, which might be the important factors that made the appearance quality poor. The activities of starch phosphorylase and Q enzyme in the grains were different in the cultivars with three type panicles and in the grains from different sites of the panicle, the differences above were concerned with grain filling speed during early and late grain filling period, grain enzyme activity differences in different sites of the panicle were found in the cultivars with poor appearance quality. Chlorophyll contents of flag leaves during heading and maturing stages were correlated with quality characters. The gel consistency had the tendency to be more rigid and the protein content increased with the increase of chlorophyll content in the flag leaves.