Rice quality, which is intricately connected to market value and human
nutrition, is sensitive to weather conditions. However, the relative
importance of the different climatic factors is poorly understood, and the
impact of climate change on rice quality has been little studied on a large
scale. Here, using more than 35 years of rice quality data, we present the
first effort to determine the key climate variables driving rice quality in
China and Japan. Results show a significant decline in high quality rice
rate (HRR, an indicator of rice quality), mainly driven by warm nighttime
temperatures when they exceed a critical threshold estimated at 18°C and
12°C in China and Japan, respectively. Climate projections suggest a
continuing decreasing trend in HRR under moderate and high emission
scenarios by 2100. These findings emphasize the importance of breeding new
heat tolerant cultivars to maintain stable rice quality in the future.



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