Abstract: The present investigation was undertaken to estimate the combined effects of hybridization and Ethyl Methane sulfonate (EMS) on variability of polygenic traits associated with productivity in F1M1 generation of sesame crop. Three popular and well adapted sesame varieties were crossed and three non-reciprocal crosses were made. These F1s seeds were divided into two lots and one lot from each cross were used for EMS treatment. F1s seeds of each cross were presoaked separately in distilled water overnight followed by treating with 0.5 percent freshly preparer EMS solutions for 3 hours. Seeds of total nine populations (three EMS treated populations “F11M1”, three respective crosses as controls “F1s" and three parents) were shown in a randomized block design (RBD) with 3 replications during the summer season, 2017. Observations were recorded on four polygenic traits and statistical analysis like ANOVA of mean, standard deviation and CV was carried out and the significant differences among various treatments were tested by ' F' and t - tests. Reduced mean and increased standard deviation was observed for plant height whereas increased mean and standard deviation was observed for number of capsules per plant and seed yield per plant in EMS treated F11M1s. Increased in variability in mutant populations for above characters might be due to breakage of linkage between favorable and unfavorable genes. Three F1M1 populations used in this study showed differential sensitivity with respect to different quantitative characters. The changes in different polygenic traits of mutant populations than respective controls must have arisen through induced micro-mutations. The relative magnitudes of genetic change in the hybrids as a result of chemical mutagen would be better known from analyses in later generations.