The experiment was conducted at the Experimental Farm of Horti. Depar., of Faculty of Agric.,
Moshtohor, Banha Univ, Egypt in two seasons 2020/2021 or 2021/2022 to evaluate the effect of mutagens
(gamma at 100, 200, 300 Gy) and chemical mutagens (EMS) is a mutagenic, carcinogeni with formula
C3H8SO3,(DEMS) formula (CH3O)2SO. at 0.1%, 0.2% and 0.3%. Hibiscus plant is considered one of the very
important ornamental plants, The effect of mutagens on the growth and flowering of Hibiscus was studied, The
ISSR-PCR technique was also used to determine the genetic variation among the hibiscus plants. Hibiscus were
irradiated with four different levels of gamma radiation (control, 100, 200, 300 Gy) or EMS and DEMS) at a
concentration of (0.00, 0.1%, 0.2% and 0.3%) However, the irradiation results showed that gamma rays at 100Gy
treatment significantly increased plant height and number of leaves in the two seasons. The best treatments was
achieved with Gy at 100 Gray, followed by Ethyle methane sulphonate at 0.1% gamma rays at 200 Gray
treatments gave the next results, but gamma rays at 300 Gray caused a significant decrease in plant height in both
seasons, and the optimal dose of radiation per plant was calculated between treatments because of the
determination obtained in dry weight, and this factor used to determine is generally high. Gamma ray doses had
adverse effects on the growth of hibiscus, and this study showed that high doses of irradiation (200 to 300 Gy) of
hibiscus inhibited their growth and significantly decreased them.