Determination of optimum dose of chemical mutagen for large scale seed treatment of white seeded sesame (Sesamum indicum L.) varieties.

In the present study two white seeded sesame varieties VRI 3 and SVPR 1 were treated with seven different concentration viz., 0.2 %, 0.4 %, 0.6 %, 0.8 %, 1 %, 1.2 % and 1.4 % of chemical mutagen Ethyl Methane Sulphonate (EMS). Germination percentage and germination index were tested using two different germination methods. Seed germination percentage and germination index was decreased with increased doses of EMS in both the varieties. The higher concentration of EMS completely arrested the seed germination. The optimum dose of the mutagen should be tested to maintain the require plant population in the M1 generation and increasing the effectiveness and efficiency of the mutagen. LD 50 value was determined using probit analysis. For SVPR 1 and VRI 3, LD 50 value was found to be 0.36% and 0.44 % respectively. For fixing the lethal dose for the chemical mutagen, Pro tray method of germination test was found to be reliable than germination paper method.