Agriculture Reference
In-Depth Information
rice cropping to only one season. On the other hand, it is well
known that respiration is low at low temperatures. The low
respiration due to low night temperatures during the grain
development phases of rice plants planted outside of the TCTC
zone may favour grain development and fi lling. This high yield
(Table 28) provider excel the critical temperatures for different
phases of rice plants.
Table 28
Critical temperatures at different growth stages of rice plants (adopted
from Yoshida 1978).
Growth State
Critical temperature (ºC)
Optimum
temperature
(ºC)
Low
High
Germination
16-19
45
18-40
Seedling emergence
12
35
25-30
Rooting
16
35
25-28
Tillering
9-16
33
25-31
Panicle initiation
15
-
-
Panicle differentiation
15-20
30
-
Anthesis
22
35-36
30-33
Ripening
12-18
>30
20-29
The optimum planting time of transplanted aman in
Bangladesh is August. But delay in transplanting in late planting
exposes the reproductive phases as well as phenological events
of crop in an unfavourable temperature regime thereby causing
high spikelet sterility and poor growth of the plant (Nahar et
al. 2009).
Effects of low temperature stress in transplanted aman rice
varieties mediated by different transplanting date are noted on
the yield and its components (Tables 29 & 30).
