Induced mutagenesis is an effective strategy for generating novel genetic variability and accelerating crop improvement in sorghum. The present study was conducted at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, India, during 2023–25 to evaluate dose-dependent radiosensitivity, mutation induction and phenotypic variability in the sorghum genotype ICSV 18002 following gamma irradiation. Radiosensitivity assessment revealed a progressive reduction in seedling height with increasing radiation dose and the LD50 was estimated at approximately 230 Gy, corresponding to a 50 % reduction in seedling height relative to the control. Screening of the M2 population identified chlorophyll-deficient mutants with a mutation frequency of 1.0 %, confirming effective mutation induction. Frequency distribution and genetic parameter analyses indicated substantial induced variability for several agro-morphological and yield traits, such as plant height (PH), internode length (IL), stem girth (SG), panicle length (PL), panicle width (PW), disease score (DS), seed yield per plant (SYPP) and hundred-seed weight (HSW). High genotypic variability coupled with high heritability and genetic advance was observed for SYPP, DS, SG, PW and HSW, suggesting strong prospects for direct selection. Correlation analysis in the M3 generation showed that yield was primarily associated with panicle architecture, particularly PW and PL, while reduced disease incidence contributed positively to productivity. Principal component and hierarchical cluster analyses revealed considerable phenotypic divergence among mutant families, indicating the generation of diverse trait combinations. Standardised deviation (Z-score) analysis identified several superior mutants exhibiting early flowering (74.00 days compared with 79.33 days in the control), reduced PH (278.33 cm compared with 360.56 cm in the control), higher SYPP (up to 63.90 g compared with 16.06 g in the control) and increased HSW (up to 3.49 g compared with 2.21 g in the control). Parent-progeny analysis indicated stronger transmission of structural vegetative traits than complex yield traits, suggesting the need for further generational stabilisation for reliable selection. Overall, the study demonstrates the effectiveness of gamma irradiation in generating useful variability and identifies promising mutant lines for sorghum improvement.