BSc-MSc (Integrated)

The food security of more than half of the world population depends on
rice.
Studies suggest that global climate change is going to affect the food
production through temperature and water stress and this affect the rice
production around the globe. The present study tried to elucidate the influence of
varying soil moisture status on rice productivity and evaluate the strategies for
increased water use efficiency in a climate change adaptation strategy. The study
was conducted during May 2016-September 2016 at RARS, Pattambi in variety
Jyothi. The treatment combination included the presence or absence of hydrogel
along with 4 different levels of irrigation (IW/CPE=2, IW/CPE=1.5, IW/CPE=1
and IW/CPE=0.5). The results showed that the various irrigation levels and
hydrogel application had a significant impact on the physiology of rice. Hydrogel
application improved the soil moisture availability and increased plant
establishment.
The maximum plant height was observed for the treatment
IW/CPE=2 (105.30 cm) without hydrogel. The hydrogel effect on plant height
was significant only up to the booting stage. Hydrogel had its significance on
number of tillers only at the vegetative stage of the plant, while, interaction was
significant at the vegetative, reproductive and ripening stages. The higher value
(19.67) of tiller number was recorded for the treatment IW/CPE=1.5 with
hydrogel.
LAI was not affected by the application of hydrogel.
Only the
irrigation treatments had a significant effect on LAI, of which the treatments
IW/CPE=2 (2.72) and IW/CPE=1.5 (2.61) recorded the maximum LAI. Higher
number of primary branches per panicle was recorded for plants with hydrogel
(10.25). The number of panicle per hill was more for the treatment IW/CPE=1.5
without hydrogel (9.20). The number of filled grains produced per panicle is
more for plants with hydrogel (86.00). 1000 grain weight observed was higher for
the treatment IW/CPE=2 (27.23 g) without hydrogel. Hydrogel did not have any
significant effect on the plants physiological parameters like booting, heading,
flowering, number of days taken for active tillering and panicle initiation. The
more stressed plants took the maximum number of days to booting, heading,
flowering and panicle initiation. For the treatment IW/CPE=0.5, there seen no
sign of 50 percent flowering and consequently, it did not attained physiological
maturity. Hydrogel and irrigation had a significant impact on grain yield. Even
though the higher yield (7014.63 kg ha-1) was observed for the irrigation level
IW/CPE=2 without hydrogel, the mean average value of grain yield of plants
treated with hydrogel is higher than plants treated without hydrogel (4455.03 kg
ha-1 and 3951.80 kg ha-1 for with and without hydrogel). It can be concluded that
hydrogel had significance only when the irrigation level was low (IW/CPE=1.5
and IW/CPE=1). However, at extreme low water level (IW/CPE=0.5) and high
water level (IW/CPE=2), hydrogel failed to exhibit any beneficial role.
Under the projected climate scenario using RCP 4.5, it was found for the
year 2030 the maximum yield was observed for the treatment IW/CPE=2 (6010
kg ha-1), followed by comparable yield in the treatment IW/CPE=1.5 (5997 kg ha-
1
). The production was found to be less in the treatment IW/CPE=1 (3504 kg ha-1)
and nil to the treatment IW/CPE=0.5. For the year 2050 and 2080, the maximum
yield was for the treatment IW/CPE=2.