[en] Variability in a crop plant can be increased either by hybridization among diverse genotypes or through induced mutation. To harness more variability, mutation has been superimposed on hybridization in several crops. An attempt has been made to study the variability generated by hybridization and mutagenesis in cowpea in the present investigation. The evaluation of about 200 germplasm lines of cowpea, revealed the superiority of C-11 and C-70 in respect of pod length, number of pods per plant and boldness, while KM-1, distinctly determinate in nature, thus acting as source for creation of different plant types which is an important aspect in cowpea breeding. C-152 is a locally adopted variety but lacking in some of the desirable features that are present in C-11,KM-1 and C-70.Therefore it was planned to attempt hybridization with C- 152 as base and C-11,KM-1 and C-70 as the different sources of specific features. But as outlined above, since the combination of mutation is expected to release more variability subjected for an appropriate dose of gamma radiation. The resulting M₂ and F₂M₂ populations of different crosses were evaluated for comparing their relative efficiency in generating variability of quantitative characters. The F₂M₂ population of C-152 x C-11 showed highest mean values for plant height, number of pods per plant and yield. Variance and range values were high in F₂M₂ populations for all the characters except number of seeds per pod. The irradiated population of C-152 x KM-1 proved to be superior in producing greater frequency of transgressive segregants for individual traits. Irradiated heterozygous population produced more variability than that of irradiated parent (C-152 M₂) and control. (author)