[en] Pennisetum americanum cv. Awn Selected, ex-Bornu, Japan Bajra, and B-18 were treated with 0, 5, 10, 15, 20, 30 and 35 kR of gamma rays. Significant decrease in plant height was observed in cv. Awn Selected whereas in cv. ex-Bornu, plant height significantly increased in the irradiated population. In cv. Japan Bajra, an increase (P>==.01) in plant height was observed in 30 kR and 25kR treatments whereas in cv. B-18 a decrease (P>==.01) in plant height was noted at 15, 20, 25, 30 and 35kR doses. Regression analysis showed that the rate of reduction of tiller number following gamma irradiation was highest in cv. Japan Bajra followed by Awn Selected and B-18. Different doses of gamma rays had no significant effect on stem circumference. Genotypic differences as well as the differences due to various radiation treatments were highly significant (P>==.01) with respect to seed index. Possibilities of inducing useful mutations in pearl millet are discussed. (authors)