Differential Impacts of Whole-Growth-Duration Warming on the Grain Yield and Quality Between Early and Late Rice (Oryza sativa) in a Double Rice Cropping System

Abstract

The impacts of whole-growth-duration warming on grain yield and quality in a double rice cropping system remain largely unknown. In this study, a 2-year field whole-growth-duration warming experiment was conducted with two inbred indica rice cultivars (Zhongjiazao 17 and Xiangzaoxian 45) for early season and two hybrid indica rice cultivars (Wanxiangyouhuazhan and Tianyouhuazhan) for late season, respectively. The results showed that whole-growth-duration warming did not affect early rice yield but significantly decreased late rice yield, which was caused by the decreased grain weight that may be related to the reduced translocation of dry matter accumulated during the pre-heading phase under warming. Whole-growth-duration warming improved the milling quality of late rice but decreased that of early rice; however, the chalky rice rate and chalkiness degree were increased by 20.7% and 33.9% for early rice, and 37.6% and 51.6% for late rice under warming, respectively. We found that the crude protein content of milled rice was significantly increased by warming in both early and late rice, which would result in the deterioration of eating quality. Besides, compared with the control treatment, the setback of late rice was significantly reduced by 17.8% under warming, while that of early rice was not significantly affected by warming. These results suggest that the negative impacts of whole-growth-duration warming on grain quality varied between early rice and late rice to some extent. In summary, adaptation in both rice breeding and agronomic practices is needed to alleviate climate warming on the production of the double rice cropping system.