Effects of climate change on rice production and adaptive technologies

Recent research findings on rice responses to CO2 concentration and air temperature in growth and yield are summarized to parameterize the responses for growth simulation models and to explore adaptive production technologies. Season-long doubling of CO2 increased rice biomass by about 25% averaged over the reported data obtained under nearly field conditions, while high temperatures may cause decreased rice yield mainly because of high-temperature-induced spikelet sterility, which would be worsened by elevated CO2. Key traits associated with rice adaptation to climate change and their genetic variations are discussed. The effects of climate change on rice production in Japan were simulated by the rice growth simulation model SIMRIW. It was predicted that a 1.5°C increase in T50 (the daily maximum temperature at which spikelet fertility becomes 50% because of high-temperature damage) would remarkably mitigate negative effects of climate change in many prefectures in central and southern Japan and increase total rice production in Japan by about 5%. Model simulation under various adaptive technologies indicates that the combination of advanced transplanting and the adoption of later-maturing cultivars may help to exploit the advantage of elevated CO2 climates for rice production in Japan, although this greatly depends on prefectures.