ABSTRACT
Three sesame genotypes (Rama, SI 1666 and IC 21706) were treated with physical (γ-rays: 200 Gy, 400 Gy or 600 Gy) or chemical (ethyl methane sulphonate, EMS: 0.5 percent, 1.0 percent, 1.5 percent or 2.0 percent) mutagens and their mutagenic effectiveness and efficiency were estimated in the M2 generation. The M3 generation was used to identify the most effective mutagen and dose for induction of mutations. The average effectiveness of EMS was much higher than γ-rays. The lowest dose of γ-rays (200 Gy) and the lowest concentration of EMS (0.5 percent) showed the highest mutagenic efficiency in all genotypes. Analysis of the M3 generation data based on parameters such as the variance ratio and the difference in residual variances derived from the model of Montalván and Ando indicated that 0.5 percent concentration of EMS was the most effective treatment for inducing mutations.