Vergara - 1976 - Physiological and morphological adaptability of ri

190 crux-tars AND RICE
SD 0t temperature t°Cl
SDol sunshine tioursthrl
4 '- - 2.0
3 \-- — l5
Z —
m IO
—=-—
Heading
0 | | | | | | | | | | | 0
-6O -4O -2O O 02D 040
Stage from heading time (11015)
2. Changes in standard deviations (SD) of temperature
and sunshine hours in the data. Value averaged for 20
days: n — 22R.
1
influenced strongly by the climatic factors at the inherent stage. The author.
using field data, intended to elucidate the changing patterns in climatic effectiveness
on individual yield components and to determine the stages most
sensitive to climatic factors. The differences in climatic effectiveness among
various growth stages were expressed by comparing the multiple correlation
coefficients (R ). which were calculated from temperature (t) and sunshine hours
(s) at each stage, and a yield component (l1). Another expression was made by
comparing the gradients of r-l’, curves or s-Y, curves at each stage.
The second procedure is to find good mathematical models which serve to
express the complex surface composed of t. s, and 1' dimensions.
The selection of sensitive stage and determination of model are mutually
dependents Needless to say. the R values are computed by some model. If the
model is inadequate, the R values in every stage become lower. Thus. it is
difficult to find the sensitive stage. On the other hand. if the climatic data at
insensitive stage are used to improve a model. a good result is not obtained
One of the methods for avoiding such a vicious cycle is to use data which
are stratified by certain ranges oft or s. The surface composed of I, s, and Y,
dimensions is very complex with a wide range of! and s, but monotonously plane
with a narrow range stratified by 1 or s (Fig. 3).
When the data \vere stratified by" temperature (Fig. 3a). the s-Y, relations
were Sl10\Vll by the following model:
__
--
Y, = bit + bps + 11,1 + c (type I)
where