[Objective] By investigating of change rule rice starch RVA profile properties and the influence of cold tolerance on rice quality,the aim was to provide scientific references to the breeding of new cold-tolerant japonica rice varieties with high quality in the Yunnan plateau.[Method] Four cold-tolerant and five cold-sensitive japonica rice cultivars were grown at three locations with different altitudes in Yunnan plateau to investigate rice starch RVA profile characteristics.[Result] The results showed that with increasing altitude,the setback viscosity in cold-sensitive cultivars increased significantly,while the peak viscosity and breakdown viscosity decreased significantly.However,the peak viscosity and breakdown viscosity in cold-tolerant cultivars initially decreased and then gradually increased with rising altitude,whereas the setback viscosity initially increased and then decreased.[Conclusion] The starch RVA parameters of cold-tolerant cultivars were less sensitive to different environments than those of cold-sensitive cultivars.Cooking and eating quality of cold-tolerant cultivars had relatively stable trends with rising altitude,whereas cooking and eating quality of cold-sensitive cultivars had a trend toward inferior.
[Objective] This study aimed to investigate the variation characteristics of Yunnan and Korean japonica rice quality under different environmental conditions in Yunnan Plateau. [Method] Ten Yunnan japonica rice varieties and six Korean japonica rice varieties were selected to investigate the effects of ecological conditions on grain quality characteristics and starch RVA profile characteristic values of Yunnan and Korean japonica rice. [Result] The coefficient of variation of Yunnan and Korean japonica rice reached the maximum in setback viscosity (SBV). The coefficients of variation of brown rice length (BRL), chalkiness rate (CR), amylose content (AC), protein content (PC), alkali digestion value (ADV), final viscosity (FLV), setback viscosity (SBV) and peak time (PeT) of Yunnan japonica rice varieties were significantly higher than those of Korean japonica rice, while other grain quality characteristics were contrary. With the increasing altitudes, BRL, brown rice width (BRW), length-width ratio (L/W), whiteness (WH), AC, ADV, FLV and consistence viscosity (CTV) of Yunnan japonica rice and BRL, BRW, WH, PC, peak viscosity (PKV), hot viscosity (HTV) and breakdown viscosity (BDV) of Korean japonica rice were significantly reduced , while CR, PC, HTV and PeT of Yunnan japonica rice and L/W, AC, ADV and CTV of Korean japonica rice significantly increased, but CR of Korean japonica rice showed no significantly variation. PKV, BDV and pasting temperature (PaT) of Yunnan japonica rice and PaT of Korean japonica rice showed an upward trend after an initial drop with the increasing altitudes, while SBV of Yunnan japonica rice and FLV and PeT of Korean japonica rice were contrary. [Conclusion] This study provided theoretical basis for breeding of japonica rice in Yunnan Plateau.
