Yoshida und Hara - 1977 - Effects of air temperature and light on grain fill

106 S. YOSHIDA <strong>and</strong> T. HARA
Downloaded by [Universitaetsbibliothek Giessen] at 15:43 06 April 2015
To better <strong>und</strong>erst<strong>and</strong> how <strong>temperature</strong> during the grain filling period affects grain
weight, the grain weight was plotted against the daily mean <strong>temperature</strong>, regardless <strong>of</strong>
the day <strong>and</strong> night <strong>temperature</strong>s (Fig. 7). There was a smooth <strong>and</strong> consistent pattern in
the changes in grain weight as affected by the daily mean <strong>temperature</strong> in both IR2(}
<strong>and</strong> Fujisaka 5 rices, except with Fujisaka 5 when the difference between the day <strong>and</strong>
night <strong>temperature</strong> was 18°0. The maximum grain weight <strong>of</strong> Fujisaka 5 rice was.
achieved at the low <strong>temperature</strong> range, while the grain weight <strong>of</strong> IR20 remained high
<strong>and</strong> stable at the high <strong>temperature</strong> range. This implies that <strong>temperature</strong>, regardless.
<strong>of</strong> day or night, affects grain weight, <strong>and</strong> such effect <strong>of</strong> <strong>temperature</strong> is best related tathe
daily mean <strong>temperature</strong>. Thus, within the <strong>temperature</strong> range between 14° <strong>and</strong>
34°0, the daily mean <strong>temperature</strong> appears to be the most meaningful expression by
which to describe the effect <strong>of</strong> <strong>temperature</strong> on ripening <strong>of</strong> IR20 <strong>and</strong> Fujisaka 5 rices.
In the continent type <strong>of</strong> climate, large differences in the day <strong>and</strong> night <strong>temperature</strong>s
are common (15). A night <strong>temperature</strong> <strong>of</strong> 15°0 has been reported to prevent
or delay panicle initiation <strong>of</strong> rice even when the day <strong>temperature</strong> is maintained at 30°C
or 33°0 (16-18). In the present experiment, however, the large difference <strong>of</strong> lBoe
between day <strong>and</strong> night <strong>temperature</strong>s appeared to have an adverse effect on the ripening
<strong>of</strong> Fujisaka 5 rice rather than a low night <strong>temperature</strong> per se.
At Los Banos, Philippines, high yields are normally achieved in experimental
fields in the dry season when rice matures in April or May. These two months are
characterized by high <strong>temperature</strong>s <strong>and</strong> high solar radiation. In terms <strong>of</strong> yield components,
high yields in the dry season crop are clearly associated with a large grain
number per square meter (29). In addition, however, high <strong>temperature</strong> does not
appear to have any noticeable adverse effects on grain filling, probably because IR2()
rice <strong>and</strong> other indica varieties are well adapted to high <strong>temperature</strong>s during the grain
filling period (Fig. 7).
REFERENCES
1) Anu, R., SAWAMURA, H., <strong>and</strong> KmolNo, S., Physiological studies on the mechanism <strong>of</strong> crop plants. The
effect <strong>of</strong> the <strong>temperature</strong> upon the behavior <strong>of</strong> carbohydrates <strong>and</strong> related enzymes during the ripening
<strong>of</strong> rice plant, Proc. Crop Sci. Soc. Japan, 27 (4),405-407 (1959)
2) llANYu,J., UCHIJIMA, T., <strong>and</strong> SUGAWAJlA, S., Studies on the agro-climatological method for expressing
the paddy rice products (Part I). An agro-climatic index for expressing the quantity <strong>of</strong> ripening <strong>of</strong>"
the paddy rice, Bull. Nat. Tolwku Agr. Exp. Sta., 34, 27-36 (1966)
3) MATSUSHIMA, S., MANAKA, K., <strong>and</strong> TSUNODA, K., Analysis <strong>of</strong> developmental factors determining yield
<strong>and</strong> yield prediction <strong>and</strong> culture improvement <strong>of</strong> lowl<strong>and</strong> rice. XXXIX. On mechanism <strong>of</strong> ripening
(5). XL. On the mechanism <strong>of</strong> ripening (6), Proc. Crop Sci. Soc. Japan, 25, 203-206 (1957)
4) MATSl.JSHIMA, S. <strong>and</strong> TSUNODA, K., Analysis <strong>of</strong> developmental facton determining yield <strong>and</strong> its application
to yield prediction <strong>and</strong> culture improvement <strong>of</strong> lowl<strong>and</strong> rice. XLV. <strong>Effects</strong> <strong>of</strong> <strong>temperature</strong>
<strong>and</strong> its daily range in different growth stages upon the growth, grain yield <strong>and</strong> its constitutional factors.
Proc. Crop Sci. Soc. Japan, 26, 243-244 (1958)
5) MATSUSHIMA, S. <strong>and</strong> TANAKA, T., Analysis <strong>of</strong> developmental factors determining yields <strong>and</strong> its appli-