Comparison of temperature-gradient chamber experiments at different latitudes for estimating the effects of global warming on the heading date of paddy rice.

Abstract

We designed an inter-latitudinal temperature gradient chamber (TGC) experiment to obtain data for analyzing the effects of global warming on paddy rice production in Japan. TGC experiments were carried out at three sites of different latitudes: Sapporo, Morioka and Kumamoto. The TGCs at each site were controlled to maintain an air temperature gradient of 2 with water temperature treatment (heated 2 and unheated, except for Kumamoto) to grow eight rice varieties: Nikomaru, Reiho, Nipponbare, Koshihikari, Hitomebore, Sasanishiki, Akitakomachi and Kirara397. The higher temperature accelerated the heading date of all varieties in Sapporo and Morioka, but not Kumamoto. The relationship between the cumulative air temperature from the 5th leaf stage to the heading stage (CAT5H) and the temperature gradient in the TGC at each site suggested that the difference in CAT5H among the regions was attributable to day length, and the fact that Kirara397, Akitakomachi, Sasanishiki and Hitomebore have little sensitivity to the photoperiod, whereas Reiho, Nikomaru and Koshihikari exhibit a greater sensitivity to the photoperiod, although the critical day length of Koshihikari was longer than that of the other two varieties. The development of the rice plant depends on both air and water temperatures and the degree of dependency is based on the type of maturity. These results confirm that the effect of global warming on the development of the rice plant and paddy rice production will differ by region (latitude) and variety. Thus, inter-latitudinal TGC experiments are useful for gathering data to estimate the effects of global warming on paddy rice production.

Assessment of paddy rice heading date under projected climate change conditions for Hokkaido region based on the field experiment

“…4a), leading us to conclude that TGC experiments are likely to overestimate the effect of temperature on heading date. Although the difference in air temperature between treatments in the ODE experiment (2.5 : between C08S and ODE09M) was higher than that in the TGC experiment (1.8 : between TGC-TL plot and high-temperature (TGC-TH) plot; Hamasaki et al, 2010), the delay in heading due to warming estimated by the ODE experiment and the TGC experiment was equivalent for Koshihikari (18 days for both ODE and TGC), Hitomebore (15 days for ODE and 13 days for TGC), and Akitakomachi (10 and 11 days, respectively) (Fig. 4b).…”

“…Table 1 also indicates the data on heading dates from a TGC experiment (Hamasaki et al, 2010). The heading date of Koshihikari and Akitakomachi in low-temperature plots in TGC (TGC-TL), which was controlled to be approximately the same as the outside temperature, was 2 days later than that in our uncontrolled, open paddy field (C08S; Table 1) (Fig.…”

“…On the other hand, temperature gradient chamber (TGC) experiments have been made to analyze paddy rice properties under simulated climate change conditions (e.g., Kim et al, 1996;Hamasaki et al, 2010). The TGC is a kind of greenhouse or tunnel introduced by Mihara (1971), which has an air inlet at one end and exhaust fans at the other end.…”

“…We therefore estimated the effect of warming in Sapporo on rice cultivation by using the results of ODE experiments in Morioka in 2009. Then, we compared the ODE experimental results to previous TGC experiment by Hamasaki et al (2010) to show the difference between the open-field experiment and the chamber experiment close to open-field, and to previous model simulation by Toritani et al (1999) to examine the difference between the open-field experiment and the model application to extrapolation range of climate change projection.…”

Panicle emergence pattern and grain yield of rice plants in response to high temperature stress

“…The experiment was conducted using TGCs, as reported in our previous studies (Hamasaki et al, 2010;Maruyama et al, 2013), to expose rice plants to different temperatures. The TGCs at KO-ARC are pipe-framed greenhouses (3.6 m width × 3.0 m height × 30 m length) covered with 0.1-mm-thick polyolefin film (TokanAce-N; Tokan Kosan, Tokyo, Japan).…”