Rice grain quality degradation and economic loss due to global warming in Japan

Abstract

Global warming is predicted to have significant impacts not only on crop productivity but also on crop quality, leading to economic loss. In the present study, focusing on grain quality of rice in Japan, we assessed the impact of global warming on the occurrence of low quality rice grain called 'chalky rice grain', and the incurred economic loss. Using 10 future climate scenarios and a simulation model to estimate the occurrence of chalky rice grain, we showed that global warming will double the occurrence of chalky rice grain by the 2040 s under RCP8.5. This corresponds to one third of paddy rice fields in Japan showing a decrease in grain grade. This would produce an annual economic loss of 401.4 million US$/yr under RCP8.5 in the 2040 s. These results suggest that the development and implementation of national and local adaptation strategies are urgently needed for rice production in Japan.

Model‐based evaluation of climate change impacts on rice grain quality in the main European rice district

“…The higher temperature in post-flowering led to the shortening of grain filling and to suboptimal conditions for protein synthesis, thus reducing the N accumulation in grains and its conversion to protein (Cheng et al, 2010;DaMatta et al, 2010). While the projected incidence of milky white grains in Gladio slightly increased (average +4.5%), the Loto results depicted a huge variation (14% and 60%), consistently with climate change studies carried out in Japan using comparable scenarios from AR4 (Okada et al, 2011) to AR5 (Masutomi et al, 2019; IPPC SRES. The magnitude of protein and head rice yield decreases was coherent with experiments carried out under FACE conditions (Cheng et al, 2010;DaMatta et al, 2010;Taub et al, 2008;Yang et al, 2007) revealing an average decline up to 15% and 23.5%, respectively.…”

“…Process-based simulation models represent effective research tools to address these questions, due to their capability to reproduce nonlinear responses to boundary agrometeorological conditions (Porter & Semenov, 2005). Despite a variety of models has been developed to simulate pre-harvest grain quality (Cappelli et al, 2014;Martre et al, 2011), very few studies focused on the future trends, for example, of grain nitrogen concentration in wheat (Asseng et al, 2013(Asseng et al, , 2019Erda et al, 2005;Porter & Semenov, 2005) and of chalkiness in rice (Masutomi et al, 2019;Okada et al, 2011;. These studies agree in identifying the rationalization of nitrogen fertilizations, the optimization of sowing dates, and the use of heattolerant cultivars as appropriate adaptation strategies to counterbalance the quality decay in cereals.…”

Simulating the impacts of and adaptation options for increasing air temperature on chalky rice grains in the Kyushu region of Japan

“…High air temperatures during the grain-filling period can cause chalky rice grains ( Terashima et al, 2001). The occurrence of chalky grains leads to a decrease in quality, such as appearance and taste ( Wakamatsu et al, 2007) and a degradation in the rice grain grade, inducing a reduction in farmers' income and economic loss ( Masutomi et al, 2019). Several observation and simulation studies have indicated the occurrence of chalky rice grains and a reduction in the grain grade in Japan, even under ambient air temperatures ( Terashima et al, 2001;Okada et al, 2011a;Masutomi et al, 2019).…”

Higher Temperatures during Grain Filling Affect Grain Chalkiness and Rice Nutrient Contents

“…One study reported that high temperature could reduce the starch content by up to 40% [8]. Moreover, high temperatures in the period after heading cause the emergence of chalky grains, immature thin grains, and cracked grains, leading to decreased quality of rice in external appearance and taste [7,9,10]. Some studies have found that higher CO 2 conditions can lead to increased rice yields [11][12][13], but other studies have reported reductions in nutrient grain contents under high CO 2 conditions.…”