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Screening rice genotypes for drought resistance in Egypt
A. A. Abd Allah*, M. H. Ammar and A. T. Badawi
Rice Research and Training Center,
Field Crop Research Institute, ARC, Egypt.
*Corresponding author.
E-mail:
abdnby@yahoo.com.
Accepted 20 January, 2010 |
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A
series of experiments were conducted under normal and
drought conditions to examine the magnitude of yield
response of diverse genotypes to drought stress and to
identify traits that may confer drought resistance.
Thirty-three local and exotic rice entries including 18
Egyptian genotypes (selected from Fn generation of the
breeding for drought tolerance program, Rice Research and
Training Center, Egypt), six Italian and nine Chinese rice
varieties were grown at Rice Research and Training Center
experimental farm for evaluation under normal as well as
drought conditions during 2007 and 2008 rice growing
seasons. Experiments were laid out in randomized complete
block design with three replications. Analysis of variance
indicated highly significant differences among the genotypes
for all the traits studied.
Many promising lines were found to be tolerant against
drought stress at different growth stages i.e. seedling
stage, early and late vegetative stage, panicle initiation
stage and heading stage. These lines possess useful traits
associated with drought tolerance such as early maturity
(drought escape mechanism), medium tillering ability,
medium plant height, root depth, root thickness, root
volume, dry root: shoot ratio, plasticity in leaf rolling
and unrolling (drought avoidance mechanism), in addition to
crop water use efficiency and water application efficiency.
The results showed that the genotypes viz: Giza 178, Giza
182, GZ5121, GZ 6296-12-1-2-1-1, GZ 8310-7-3-2-1, GZ
8367-11-8-3-2, GZ 8372-5-3-2-1, GZ 8375-2-1-2-1, GZ
8450-19-6-5-3, GZ 8452-7-6-5-2, GZ 1368-S-4, Augusto and SIS
R215 were the best entries under drought conditions, where
they possess many desirable traits which are useful for
drought tolerance. Among the traits studied viz: number of
tillers per plant, number of panicles per plant, 100 grain
weight, panicle weight, revealed significant genotypic
correlation with grain yield. Also, number of filled grains
per panicle depicted the highest direct contribution of
0.630 and it also show highest indirect contribution of
0.867 followed by 100 grain weight (0.850) towards grain
yield. Path coefficient analysis demonstrated that number of
panicles per plant, 100 grain weight; number of filled
grains per panicle, panicle weight should be improved in
order to increase grain yield under both normal and drought
conditions.
Key words:
Drought stress, path analysis, rice, screening. |
