Agriculture Reference
In-Depth Information
conditions, climatic shifts is impacting fruit bud differentiation pattern,
which affects time of flowering and fruit production (Ravishanker and Ra-
jan, 2011). Lower temperatures could result in early flowering and poor
fruit set due to floral abnormalities.
On the other hand, higher temperatures during flowering reduce the
effective time for pollination by pollinators, poor pollinator activities and
desiccation of pollen. The Tommy Atkins mango trees flowered within 10
weeks when held at day/night temperatures of 18/10 °C, whereas trees held
at 30/25 °C produced vegetative growth and did not flower (Nunez Elisea
et al., 1933). Higher temperature during microsporogenesis of pollen de-
creased pollen viability from 85 to 60 percent with increase in temperature
from 33 °C to 36 °C (Issarakraisila et al., 1993). While studying the effect
of higher temperature on twig drying in fruited and nonbearing four variet-
ies of mango, Reddy and Singh (2011) observed that drying of shoots was
more in fruited plants when compared to un fruited ones. Among different
varieties, Dashehari (77.28%) showed maximum twig drying followed by
Baneshan (32.0%) and Rajapari (33.93%), while lowest twig drying was
recorded in Langra (19.05%). The extent of leaf scorching in plants of
Baneshan and Rajapari was higher than other varieties. In banana, with
increase in temperature of 1-2 °C beyond 25-30 °C resulted an increased
leaf production and thereby reducing crop duration and increased produc-
tion (Chaddha and Kumar, 2011).
2.2
HIGH TEMPERATURE
Most of the plant processes related to growth and yield are high tempera-
ture dependent and there can be an optimum temperature range for maxi-
mum yield. The optimum growth corresponds to the optimum temperature
for the photosynthesis and other metabolic reactions. Plant growth and de-
velopment is speeded up in annual crops, but, in perennial crops increase
of several degrees of temperature than optimum could reduce photosyn-
thesis thereby affecting productivity through reduced growth period. The
particular crop that is currently being grown in areas where it is usually
best-adapted to the prevailing climate may not be tomorrow. A significant
increase in growing season temperatures will require shifts to new variet-
ies that are more heat tolerant and have a higher optimum temperature
for photosynthesis. Under prevailing unlimited conditions, development
 
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