关键词: 早籼稻, 乳熟期, 高温, 淀粉RVA谱, 直链淀粉含量

Abstract: Two hybrid rice varieties（Ganxin203 and Jinyou402）and four conventional rice varieties（Zhong531，B670，E134，and ST66）were used as materials They were exposed at 35℃ and 38℃ for 3 days at milk stage and compared with the controls in the field of natural temperature in the same time period The effects of high temperature at milk stage on amylose content and starch RVA profile characteristic parameters in different early indica rice varieties were discussed Furthermore，the correlation between starch RVA profile characteristic values and amylose content was analyzed The results showed that Zhong531 and B670 had a large breakdown and a low amylose content，setback，and consistency both at the controls and high temperature treatments On the contrary，E134 and ST66 had a small breakdown and a high amylose content，setback，and consistency，and the case for hybrid rice Ganxin203 and Jinyou402 was in the middle across all treatments Compared with the control，38℃ high temperature decreased significantly the breakdown of Ganxin203，Jinyou402，Zhong531 and E134，and increased significantly the setback of Ganxin203 and Zhong531，and decreased significantly the consistency of Jinyou402，Zhong531，B670and E134，respectively The processing of starch RVA profile in all treatments was broadly similar，but the morphology of starch RVA profile between varieties and temperature was slightly different The rice starch viscosity curve under 38℃ high temperature was always lower than those of the controls，while the RVA profile characteristic values of Zhong531 and B670 were different from those of the controls Moreover，the amylose content of rice starch was significantly correlated with RVA profile characteristic values

Key words: Early indica rice, Milk stage, High temperature stress, RVA profile, Amylose content