Abstract:

Under the field condition, two varieties (Indica and Japonica rice) were used to study the effects of panicle nitrogen fertilizer on the accumulation of soluble sugar and amylose content in super-grain and infer-grain of rice in order to increase grain-plumpness and improve rice quality. At the same time, the relationship between the ratio of the amylose content to amylopectin content and the grain plumpness of rice was discussed. The results showed that the change tendency of the soluble sugar was described as “L” in superior and inferior grain of rice with the growing stage. The soluble sugar content of the infer-grain was significantly higher than that of the super-grain and increased with the panicle nitrogen rising. In other words, the synthetic ability of the starch was declined with the panicle nitrogen increasing. The amylose content was basically growing in the whole grain-filling stage and decreased with the panicle nitrogen increasing. The average content of amylose in the Indica rice was higher than that of Japonica rice at the mature stage. The ratio of amylose content to amylopectin was increasing during grain-filling stage. However, the appearance time of the peak value of the ratio of amylose content to amylopectin content was different in the superior and inferior grain and most of the infer-grain was lagged behind the super-grain. Correlation analysis showed that the relationship between the ratio of amylose content to amylopectin content and grain plumpness was significant or highly significant linear positively, which indicated that the grain plumpness can be increased with the enhancement of the ratio of amylose content to amylopectin content.