Screening of EMS induced drought tolerant sugarcane (Saccharum spp. Complex) mutants employing physiological, molecular and biochemical approaches

The calli were mutagenized with 0.5% EMS and exposed to 2% (w/v) PEG-6000 for induction of the osmotic stress. Calli that survived after in vitro osmotic stress treatment put on MS media for regeneration of plants. Regenerated plants were then subjected to preliminary greenhouse pot trials to confirm drought stress tolerance. In the present study leaf area, chlorophyll content, photosynthesis rate, shoot length, root length, fresh weight and dry weight decreased with an increase in osmotic stress in tolerant mutants and normal plants, but there is less decrease in leaf area (7.5%), no. of leaves (19.9%), chlorophyll content (22.0%), photosynthesis rate (141.5%), stomatal conductance (10.9%), shoot length (9.7%), root length (4.79%), fresh weight (28.9%) and dry weight (3.8%) in tolerant mutants as compared to normal plants at higher level of osmotic stress. The transpiration rate (6.3%) was low in tolerant mutant. Proline content (7.0%) increased highly in tolerant mutant at higher water stress. RAPD primer OPK-10 produced maximum polymorphism (100%) followed by primer OPK-04 (91.67%), OPK-15 (88.89%) and OPL-03 (88.89%). Modification in all the physiological traits may be useful to use in breeding for improving drought tolerance in sugarcane.