The difference between starch chain length distribution and main quality characteristics of high resistant starch lines of japonica rice.

【Objective】 Providing a theoretical and practical basis for breeding and germplasm enhancement by means of genetic analysis on resistant starch content in japonica rice. 【Method】 Using japonica rice lines with significant differences in resistant starch content , this paper analyses differences and correlation of amylopectin chain length distribution, RVA spectral properties value, dietary fiber and amylose content and other quality characteristics between them. 【Result】 The chain length distribution of amylopectin shows significant differences between high and low resistant starch content strains . For the high resistant starch content strains, the relative percentage of the degree of short chain polymerization 5 to 12 about amylopectin content, which is obviously lower than low resistant starch content strains. However, the degree of polymerization in long chain (particularly above 13 proportions) is obviously higher than the low ones. Dietary fiber and amylose content of high resistant starch content is higher than that of low ones. And the peak viscosity, cool paste value, hot paste viscosity and breakdown value of high resistant starch content is significantly or very significantly lower than that of the low ones. The polymerization degree (DP≤12) of short chain amylopectin shows very significantly negative correlation to resistant starch content. On the contrary, the very significantly positive correlation between resistant starch content and the proportion of polymerization degree (12DP≤36) of long chain amylopectin, and the amylose content and the dietary fiber content was observed. 【Conclusion】 The resistant starch content is closely related to amylopectin chain length distribution, amylose content, RVA spectral properties value. Therefore, it could be used as a breeding index.