Countermeasures for heat damage in rice grain quality under climate change

Large-scale evaluation of the effects of adaptation to climate change by shifting transplanting date on rice production and quality in Japan

“…However, our findings suggest that the effectiveness will be limited in the case of a large increase in temperature. Many other adaption options may be available to reduce negative impacts of climate change on rice production, including cultivars having heat tolerance and / or different phenology characteristics for heat avoidance, and appropriate management in water and fertilization e.g., Morita et al, 2016 . In particular, the appropriate nitrogen applicatio n can reduce the occurrence of rice heat damage remarkably Morita et al, 2016 . Additionally, some important factors are not taken into account in this study: changes in available water resources and in the distribution of paddy field, extreme weather phenomenon including typhoon, and expansion of new disease or insect; all of which should be noted when interpreting the results derived from our investigation.…”

“…Many previous studies noted that the quality of rice grain declines when the daily mean temperature averaged over the 20 days after the heading date exceeds 26 to 27 C e.g., Wakamatsu et al, 2007;Morita et al, 2016 . The emergence of chalky grain, which causes quality degradation, can be described by a function, measured in heat degree-days, that reflects the deviation in daily average air temperature from a base of 26 C Nagahata et al, 2006;Nakagawa et al, 2008.…”

“…Relative rice production and percentage of each class based on adaptation 2 for each climate change scenario during the baseline, mid, and late periods. transplanting is generally an adaptive countermeasure and has been implemented widely in Japan in recent years Morita et al, 2016 . However, later transplanting leads to a disadvantage in yield formation because the ripening period shifts to autumn when solar radiation energy is insufficient for adequate grain filling Horie et al, 1995b .…”

“…One major cause of the recent apparent decline in rice quality is the increase of white immature kernels due to high temperature, which tends to occur when the average temperature during the 20 days after the heading date is higher than 26 or 27 C Morita et al, 2016 . Several studies have attempted to develop a model for estimating the incidence of white immature kernels from meteorological factors e.g., Nagahata et al, 2006;Nakagawa et al, 2008;Wakiyama et al, 2010;Masutomi et al, 2015;Yoshida et al, 2016 .…”

The effects of nitrogen uptake before and after heading on grain protein content and the occurrence of basal- and back-white grains in rice (Oryza sativa L.)

“…Additionally, eight pots for each level of top-dressing at the panicle formation stage were prepared for the measurement at heading. because of the high ambient temperature and the high amount of solar radiation during the day, the fan exhaust rate continued to be high causing strong wind in the TGC, so most of the grains became opaque and could not be classified into different types of chalky grains in room T3, possibly owing to the combined effect of the high temperature and strong wind (Morita et al, 2016). Therefore, we did not use the data from the T3 room in 2012 in our analysis.…”