Optimization of EMS mutagen dose for short day onion

The present experiment was conducted to investigate the effect of chemical mutagen on biological parameters such as seed germination, shoot and root length and to fix the lethal dose (LD50) of EMS in short day Indian onion cultivar Bhima Dark Red. Presoaked seeds of onion were treated with different doses (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2 % v/v) of Ethyl Methane Sulfonate. The optimal mutagenic doses were calculated using Probit Analysis based on germination percentage which were considered useful in developing onion mutagenized population to create genetic variability for various qualitative and quantitative traits. Seed germination was recorded after 7 and 12 days of sowing, while seedling parameters such as seedling height, dry and fresh weight of seedlings were taken after 12 days. Data revealed that the mutagenic agent significantly reduced seed germination and seedling growth parameters in terms of shoot and root length as compared to control. Significant reduction in the seed germination percent with the enhancement of concentration of EMS dose was exhibited.