Agriculture Reference
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minimum temperatures of 20.7 °C/3.7 °C and 27.3 °C/13.1 °C for early
and late emerging panicles respectively signifying higher temperatures
during panicle development are conducive. They also found much less
percentage of hermaphrodite flowers in some south Indian cultivars when
grown in northern India which was attributed to prevalence of lower maxi-
mum/minimum temperatures during panicle development as compared to
south Indian conditions during the corresponding periods of panicle de-
velopment.
Studies have shown, T
(Tmin
(<15 °C) during the development of inflores-
cences resulted in deformation of flowers which were smaller as compared
to those that developed at about 7 °C higher (Issarakraisila et al., 1992) and
these abnormal flowers at such low temperatures had small ovary, dark and
reduced style length, dark ovule and black another instead of the red one;
pistil abnormalities ensued (Fig. 5.2). Issarakraisila and Considine (1994)
noted, although mature pollen was tolerant to low temperatures even at
10 °C, this temperature being critical during meiosis, belowwhich the pol-
len viability falls to about 50%. They further observed, prevalence of high
temperatures of 36 °C and above during the prevacuolate meiosis stage of
microsporogenesis of pollen drastically reduced the pollen viability.
FIGURE 5.2
Inflorescence deformities due to low temperature effects (Tmin <15 °C)
during 2013 fruiting season at CISH, Lucknow.
Besides the above, unseasonal rains especially at the time of fruit bud
differentiation (FBD) could transform the already differentiated shoot
meristems in favor of reproductive ones to vegetative ones, attributable
