1 Department of Biology,
Haramaya University, P.O.Box 138, Dire Dawa, Ethiopia 2 Department of Biology, Haramaya University, P.O.Box 138,
Dire Dawa, Ethiopia 3 Melkassa Agricultural Research Center, Nazreth, Ethiopia
Drought is one of
the complex environmental factors affecting growth and yield of sorghum
in arid and semi-arid areas of the world. Sixteen elite sorghum (Sorghum bicolor (L) Moench)
genotypes were evaluated for their genetic potential to drought
tolerance at callus induction and plant regeneration
stage for drought tolerance. The
non-ionic water soluble polymer polyethylene glycol (PEG)
of molecular weight 6000 was used as osmoticum to simulate water
stress. The factorial experiment was laid
down in a completely randomized design which
comprised of a combination of two factors (genotypes and five PEG
stress level; 0, 0.5, 1.0, 1.5, and 2.0% (w/v) treatments).
Data were recorded for callus induction efficiency, callus fresh
weight, embryogenic callus percentage and
plant regeneration percentage. Significant
differences were observed among the genotypes, treatments and their
interactions for the evaluated plant traits
suggesting a great amount of
variability for drought tolerance in
sorghum. The correlation analysis also revealed strong and
significant association between embryogenic callus percent and plant
regeneration percent as well as between embryogenic callus percent and
plant regeneration percent. By taking into consideration all the
measured traits, Mann Whitney rank sum test revealed that 76T1#23
and Teshale followed by Meko, Gambella-1107 and
Melkam showed better drought stress
tolerance. Therefore they are recommended to be used as
parents for genetic analysis, gene mapping and improvement of drought
tolerance while Chelenko, Hormat and Raya appear to be drought
sensitive.
