Vergara - 1976 - Physiological and morphological adaptability of ri

476 curt-rm; AND RICE
Tabla l. (‘nntributlon of each yield component tn grain yleid.
Contribution to total variation
Variable‘ l|'l yield (‘h’)
N 60 1
I‘ and W 21.2
N and. F 75.7
N and W 78.5
N and F and W $1 4
N spikelet number per square meter. F filled grain percentage
W LOUD-grain weight
counted for S] % of yield variation; filled-grain percentage (F) and grain weight
(W) together accounted for 2] "/0. If the contribution of all the yield components
is taken as 100, which vrould be true if there were no error in measurement. the
contribution of spikelet number per square meter becomes 74% and the coinbined
contribution of filled-grain percentage and grain weight becomes 26%.
Thus. spikelet number clearly was the most important yield component limiting
yield in this experiment.
With this conclusion. it seemed more logical to examine climatic influence on
spikelet number rather than on yield itself.
Climatic factors may affect spikelet number per square meter in two ways:
(1) its influence through growth during the vegetative stage, and (2) direct influcnce
on spikelet formation during the reproductive stage.
N/S
I20
v = zrs-rorx
r=t1688"‘ 0
6O
O
‘E: I I l I I
0 24 2.5 26 27 28 29
Tamnnruhmlw“
.3. Effects on spikelet fonnation of solar radiation and
daily mean temperature during reproductive stage.