Two mutagens, physical (gamma rays) and chemical (EMS) were tested on lima bean for assessing their sensitivity. Dose/concentration were fixed by LD50 value as 16 KR for gamma rays and 40 mM concentration for EMS based on germination and survival percentage. The effectiveness and efficiency was worked out by accounting lethality, injury and sterility in M1 generation of treated seeds and spectrum of viable mutants was screened in M2 generations. It was observed that the frequency decreases with increasing dose/cqncentratlon of mutagen. EMS is more effective in producing extreme chlorophyll mutants. The physical mutagen i.e., gamma rays produced more viable mutants including early maturing plants, dwarfness and higher yielder. Gamma rays at lower dose i.e. 8 to 20 KR can be imposed to obtain beneficial mutants In limabean.
