[en] Laboratory and field experiments were conducted during 1990 to investigate the effects of different gamma irradiation doses on the various properties of M₁ generation of large seeded type green lentil pul-11 cultivar. Seeds for the laboratory experiments were irradiated at 11 doses ranging from 0 to 50 krad. Meanwhile seeds for the field experiments were irradiated at 8 doses ranging from 0 to 20 krad irradiation ⁶⁰Co was used. Results obtained for M₁ generation in the laboratory showed that the seedling height and the root length were decreased by increasing radiation doses. Under field conditions, although varying with variety, percent emergence, survived plants, number of pods and seeds, seed weight, plant height (except 2.5 and 5 krads) and first pod setting height (except 5 krad) were decreased with increasing radiation doses, when compared with their control. Statistical analysis for the above mentioned yield components showed that differences due to the doses were significant. Generally negative effects of increasing radiation doses were obtained for the mentioned yield components in the M₁ generation. The dose that decreased the growth by 50% (ED50) for green lentil (pul-11) was found to be 10.5 krad in the laboratory conditions. Meanwhile the lethal dose that kills 50% of the plants (LD50) was found to be 8 krad in the field