In vitro selection of sorghum (Sorghum bicolor (L) Moench) for polyethylene glycol (PEG) induced drought stress

Abstract

Drought is one of the main environmental factors affecting growth and yield of sorghum in arid and semi-arid areas of the world. In vitro selection of Sorghum bicolor for drought tolerance was undertaken by the use of somaclonal variation. The experiment was carried out with a collection of sixteen sorghum genotypes and tested in a completely randomized design. Data were recorded at five different PEG 6000 (polyethylene glycol) levels (0, 0.5, 1.0, 1.5, 2.0% (w/v) treatments)) on coleoptile length (CL), root length (RL), shoot dry weight (SDW), root dry weight (RDW), root number (RN) and statistically analyzed for significant differences. 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. In general, embryogenic callus induction and plantlet regeneration was found to be indirectly proportional to increased PEG concentrations. By taking into consideration all the measured traits, Mann Whitney rank sum test revealed that 76T1#23 and Teshale followed by Gambella-1107 and Melkam showed better drought stress tolerance while Chelenko appeared to be drought sensitive.