Effects of High Temperature and Strong Light Combine Stress on Yield and Quality of Early Indica Rice with Different Amylose Content during Grout Filling

Abstract

High temperature (HT) accompanied with strong light (SL) often occurs in early indica rice production during grout filling stage in southern China, which accelerates grain ripening. Two indica rice cultivars with different amylose content (Zhongjiazao17, ZJZ17, high amylose content; Xiangzaoxian45, XZX45, low amylose content) were grown under control (CK), HT, and HT+SL conditions during grout filling to determine the effects on grain yield and quality of rice. The results showed that compared with CK, HT and HT+SL significantly reduced the 1000-grain weight and filled grain rate whether in high or low amylose content early indica rice cultivars during grout filling, resulting in a significantly lower grain yield. Meanwhile, HT and HT+SL significantly decreased the milled rice rate, brown rice rate and head rice rate, whereas significantly increased chalky rate and chalky degree; and breakdown decreased and setback, pasting temperature increased in the cultivars, leading to the poor processing, appearance and cooking and eating quality of early indica rice cultivars. Compared with HT, the yield of ZJZ17 was significantly decreased under HT+SL, due to the lower 1000-grain weight. However, the effect of HT+SL on rice quality varied in the cultivars. In general, the yield and rice quality of ZJZ17 were relatively poor under HT+SL. Our results suggested that HT and HT+SL during grout filling had significant damage to the yield and quality of early indica rice cultivars, especially HT+SL, while the high amylose cultivar ZJZ17 showed a higher negative effect under HT+SL. KEYWORDSHigh temperature-strong light double stress; yield; appearance quality; cooking and eating quality Highlights HT and HT+SL during grout filling deteriorated yield and quality in the cultivars. High amylose cultivar ZJZ17 had relatively poor yield and quality of rice under HT+SL. SL can promote the synthesis of amylose in the cultivars under HT condition.

Quality Characteristics of Japonica Rice in Southern and Northern China and the Effect of Environments on Its Quality

“…Past studies have shown that the environment, especially temperature and light during the grain-filling stage, are important factors affecting the quality of rice. High temperature above the optimum impairs the accumulation of starch in the endosperm, resulting in immature starch granules packed loosely [7,8]. These characteristics increase the chalkiness degree and decrease the milled rice rate of japonica rice produced in the southern rice region [9].…”