The impact of elevated CO2 and temperature on grain quality of rice grown under open‐air field conditions

Abstract BACKGROUND Rising atmospheric CO 2 is accompanied by global warming. However, interactive effects of elevated CO 2 and temperature have not been well studied on grain quality of rice. A japonica cultivar was grown in the field using a free‐air CO 2 enrichment facility in combination with a canopy air temperature increase system in 2014. The gas fumigation (200 µmol mol −1 above ambient CO 2 ) and temperature increase (1 °C above ambient air temperature) were performed from tillering until maturity. RESULTS Compared with the control (ambient CO 2 and air temperature), elevated CO 2 increased grain length and width as well as grain chalkiness but decreased protein concentrations. In contrast, the increase in canopy air temperature had less effect on these parameters except for grain chalkiness. The starch pasting properties of rice flour and taste analysis of cooked rice indicated that the palatability of rice was improved by CO 2 and/or temperature elevation, with the combination of the two treatments showing the most significant changes compared with ambient rice. CONCLUSION It is concluded that projected CO 2 in 2050 may have larger effects on rice grain quality than the projected temperature increase. Although deterioration in milling suitability, grain appearance and nutritional quality can be expected, the taste of cooked rice might be better in the future environment. © 2015 Society of Chemical Industry