Central Rice Research Institute Annual report...2011-12

Fig. 9. Photosynthetic efficiency of rice hybrids grown under four
nitrogen levels both at vegetative and flowering stage
Photosynthesis and yield of rice
hybrids grown under four nitrogen
levels
Photosynthetic characteristics in relation
to biomass production and yield were
investigated using three rice hybrids viz.,
Ajay, Rajalaxmi and CRHR32. The result
indicated that the photosynthetic rate linearly
increased in all the hybrids when the
nitrogen level increased from N 0
(No nitrogen)
to N 200
(200 kg N ha -1 ) irrespective of
the stage of the crop (Fig. 9). The P N
per chlorophyll
(P N
Chl -1 ) was higher in all the hybrids
grown under N 200
at vegetative stage
and there was a significant increase in the
P N
Chl -1 value under flowering stage irrespective
of the rice hybrids and N levels.
The grain yield of all the rice hybrids was
influenced by the nitrogen level with highest
grain yield was recorded in Ajay (9.85 t
ha -1 ) followed by Rajalaxmi (8.70 t ha -1 ) and
CRHR32 (7.79 t ha -1 ) under N 200
(Fig. 10).
There was a significant positive correlation
between total dry matter and grain yield
with P N
in all the hybrids showing interdependence
of parameters under different nitrogen
levels (Fig. 11).
Fig. 10. Total dry matter (TDM) and grain yield of rice hybrids
grown under four nitrogen levels
Fig. 11. Correlation coefficient between total dry matter and grain yield with photosynthetic rate in rice hybrids
grown under four nitrogen levels
48 CRRI ANNUAL REPORT 2011-12