Abstract:

Starch pasting viscosity tested by Rapid viscosity Analyser (RVA) and cooking physical-chemical indices are two kinds of important evaluation parameter for the eating and cooking quality of rice. It is important to investigate these indices to select high quality rice cultivar. The objectives of this study were to investigate these rice quality indices and analyze their correlations using 18 japonica cultivars (lines) from Jiangsu Province of China, 18 Japanese Japonica cultivars (lines) and three double haploid (DH) populations derived from the cross between Wuyunjing 8 (a Jiangsu japonica cultivar) and Yueguang, Nongken 57, Xiaoqianyou (three Japanese japonica cultivars), respectively. The results showed as follows: (1) There were no significant difference in breakdown (BDV), setback(SBV) and gel consistence (GC) between cultivars(lines) of Jiangsu of China and Japan, but Japanese cultivars(lines) had higher peak viscosity (PKV), hot paste viscosity (HPV), cold paste viscosity (CPV), consistence(CSV) and amylose content (AC), and lower pasting temperature (PaT). Jiangsu and Japanese cultivars (lines) could be clustered into four types based on starch RVA profiles. The cultivars (lines) of the first type including six Japanese cultivars (lines) with superior eating quality had lower HPV, CPV, SBV and CSV, and higher PaT than those of the fourth type including six Jiangsu cultivars (lines) with inferior eating quality. (2) All the RVA profile characteristics and cooking physical-chemical indices of three DH populations had wide genetic variations and were higher than high-parent values or lower than low-parent values, among which SBV had largest coefficient of variation. (3) The tight relationship among RVA profiles was found. There were very significant（P＜0.01） positive correlations among PKV, HPV and CPV, significant （P＜0.05） or very significant positive correlations between PKV and BDV, HPV and BDV, respectively, very significant positive correlations between HPV and CSV, CPV and CSV, SBV and CSV, respectively, and very significant negative correlation between BDV and SBV. Additionally, in three DH populations, there were also same very significant positive correlation between CPV and BDV, significant or very significant positive correlations between PaT and PKV, PaT and BDV, respectively, and very significant negative correlation between PaT and SBV. (4) Cooking physical-chemical indices had tight relationship with starch RVA profiles in three DH populations. AC was significantly positively correlated to SBV and significantly or very significantly negatively correlated to PaT. GC was significantly and positively correlated to PKV, BDV and PaT, respectively, and very significantly and negatively correlated to SBV. The results suggest that HPV, CPV, SBV, CSV and PaT can be used as referenced indices in eating quality selection of Japonica rice.

Key words: Japonica, Cultivar (line), DH population, Starch RVA profiles, Cooking physical-chemical index, Correlation analysis