Water shortage stress is the most critical
abiotic factor reducing rice
yield
. Water deficit stress at whichever of the rice critical growth stage causes decline in
yield.
A field e
xperiment was conducted at the Experimental Farm of Sakha Agricultural
Research Station, Kafr
elsheikh, Egypt during 2018 and 2019
seasons,
to investigate the
effect of four irrigation intervals (continuous flooding(I1), irrigation every six days(I2),
nine
days(I3) and twelve days(I4)) on performance of five genotypes (Giza 178, IR
69625A/Giza 178, IR 70368A/Giza 178, IR 69625A/Giza 179 and IR 69625A/Giza 181). Strip < /div>
plot design, with four replications was used. The horizontal plots were assigned to
irrigati
on treatments, while the vertical plots were assigned to
rice
genotypes.
Different
drought tolerance indices such as
abiotic tolerance index (ATI), stress susceptibility
index (SSI), mean productivity (MP), tolerance index (TOL) and stress susceptibility
percentage index (SSPI)
were tested in screening superior rice genotype
s.
The results
showed that days to
50%
heading, plant height, panicle length, panicle weight, number of
effective
tillers hill
-1
, spikelet's number panicle
-1
, number of branches
panicle
-1
, seed set
(%), 1000-
grain weight
(g), number of filled grain
s panical
-1
, grain yield t ha
-1
, harvest
index (%) and biomass weight
t ha
-1
were highly significantly affected by the interaction
between
irrigation intervals
and genotypes.
The highest
values
of grain yield
were
obtained
by
IR69625A/Giza 181
under
continuous flooding irrigation
during
both
seasons
.
Based on results of different drought
tolerance indices, IR69625A/Giza 181
showed lowest values of ATI, SSI and TOL and the highest values of MP and SSPI
and
was identified as drought tolerant genotype
.