Vergara - 1976 - Physiological and morphological adaptability of ri

458 CLIMATE ANT) RICE
Table 2. Partial correlation coefficient: of tho relative docrollinq rate of loaf are: with
(1) the percentage total nitrogen content of loaves. (2) moon temperature, and (3) nolar
radiation during tho former half (A) and latter half (8)01 grain-filling period, calculated
for 1987-1971 (Miynaku at al.. 1915}.
Number o1
Station '12.34 '13.24 ‘1423 samples
A Akita 0.281 0.102 0.203 10
Sendai 0.496 0.805" 0.393 9
Takada Er Fuiiui 0.132 0.075 —0.098 10
Nagano 0.548 0.009 0.122 10
Konosu 0.263 0.112 0.025 10
Fukuyama --0.001 0.524 0.449 10
Chikugo 0.591 —0.289 0.135 10
Pooled 0.003 — 0 .046 0.178 69
B Akita 0.012 0.837" 0.144 1O
Sendai 0.390 0.223 0.747 9
Takada 8 Fukui —0.545 0.341 0.012 10
Nagano --0.185 - 0.044 0.292 10
Konosu -— — — —-
Fukuvama ~-0.768‘ 0.655 0.546 10
Chikugo 0.563 0.767‘ ——0.672 10
Pooled —0.370"‘ 0.318‘ 0.090 59
wSdgnificant at sifiafiinii i‘? ('51 level.
after heading and in the following 3-week period. with the nitrogen content of
leaf blades (2). mean daily temperature (3). and solar radiation (4). using the
IBP field experiment data (part of which is shown in Fig. 2). LRDR was calculated
according to the following equation:
LRDR = e4-
‘ —4=
Am. —
i.)
where A. and A; denote leaf area index at time t, and t1, respectively‘. The results
are shown in Table 2.
During the earlier period no correlation was significant in any items at any
stations, except for a single item at Sendai. where temperature W35 very closely
correlated with LRDR (rm. = (1.885. significant at 1% level). However. during
the later period, nitrogen content was in most cases negatively correlated. reaching
a significant level at liukuyania and also in the pooled data (rm, = 0.3?0.
significant at the 1% level). On the other hand, temperature was positively
correlated. reaching significant levels at Akita, Chikugra, and in the pooled
data (rm, = 0.318. significant at the 5% level). In contrast. solar radiation
showed no consistent tendency".
From these results it has been concluded that in the earlier half of the grainfilling
period. leaf area decrease had no close relationship with nitrogen. temperature.
or radiation. except for the case at Sendai where it was significantly
correlated with temperature. ln the latter hall" of the peritid. nitrogen content
and temperature seemed to exert considerable influence on leaf area decrease;
the lower the nitrogen content and the higher the temperature the greater the
decrease in leaf area tended to be.