الفهرس 
Drought tolerance in riceOnly 14 pages are availabe for public view
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Abstract
Mohamed Ali Mohamed Ali. Mutagensis and biotechnological studies
for abiotic stress tolerance in rice. Unpublished M.Sc. Thesis,
Department of Genetics, Faculty of Agriculture, Ain Shams
University, 2016.
Water stress is one of the major threats for sustainable rice
productivity. Combining drought resistance with yield potential is the
most promising challenge for the rice breeders. The present study was
conducted using three local rice cultivars (Oryza sativa L.); Sakha 101,
Sakha103 and Giza 178, in addition to IET 1444 indica rice cultivar to
explore their response against three water stress intervals. Grains of the
cultivars were treated with different doses of gamma rays (200, 250 and
300 Gy) to create genetic variation to obtain drought tolerant and earlier
genotypes via selection in the field and in vitro in M2 and M3 generations.
Significant differences were observed between genotypes and their
parents in all generations for most studied traits under both well watered
and stress conditions. The most tolerant genotypes were identified due to
their performances in the field. Callus initiated from mature embryos of
all tested genotypes, then maintained on MS medium containing different
concentrations (5, 10 and 15%) of Polyethylene glycol (PEG). Callus
growth traits and number of regenerated plants decreased with increasing
PEG concentration. Forty six SSRs primers were used to assess the 10
elite genotypes and their four original parents. The total number of
amplified bands and polymorphic bands were (189 bands), representing
100% polymorphism. Thirty nine unique markers identified the drought
tolerant genotypes and may be responsible for tolerance to drought.
Key words: Rice, Gamma radiation, Mutations, Drought tolerance, Early
maturing, Mature embryo, Callus induction, Plant
regeneration, PEG, SSRs.