Induced genetic variability, heritability and genetic advance in sesame (Sesamum indicum L.).
Three widely adapted sesame genotypes Rama, SI 1666, and IC 21706 were induced by 200 Gy, 400 Gy, and 600 Gy doses of γ rays as well as by 0.5%, 1.0%, 1.5%, and 2.0% concentrations of ethyl methane sulfonate (EMS) separately. Mutant generations from M1 to M2 were raised to assess the extent of variability, heritability, and genetic advance for yield and important yield components in mutant populations. Mutations surpassed the magnitude of variability over the control population in both generations. Mutagenic treatments caused a shift in the mean values of quantitative traits in both positive and negative directions, albeit the magnitude of the shift varying with mutagen, its dose, parental genotype, and character under consideration. Lower doses of mutagens were more proficient for induction of mutations. The chemical mutagen (EMS) was much more effective than the physical mutagen (γ rays) in producing polygenic variability. The genotype IC 21706 and the treatment using 0.5% concentration of EMS appeared to be the best for engendering variability, highlighting their potentiality for selecting higher yielding plants in early generations. In the M2 generation, there was considerable increase in genetic estimates for all the metric traits, as compared with that in the M1. In general, estimates of genetic variability and heritability dwindled with increasing doses of γ rays and EMS. All genotypes showed a promising increase in genotypic variability, heritability and genetic advance for all traits, implying that these characters can be transmitted to future generations. This means that a significant gain could be achieved through selection in early generations.