The Effect of Acute Gamma Irradiation on the Radiosensitivity and Morphology of Gomphrena pulchella

Gomphrena pulchella, commonly known as the button flower, stands as an exotic ornamental species celebrated for its beauty in landscaping, fencing, and potted displays.  Gamma irradiation-induced mutation has emerged as a promising strategy for induced-mutant breeding. Nonetheless, the application of gamma radiation on G. pulchella remain limited. This study aimed to determine the optimal effective dose by radio sensitivity test and evaluate the effects of radiations on G. pulchella cutting. The cuttings of G. pulchella were irradiated using acute gamma at 0, 10, 20, 40, 60, 80 and 100 Gy. Each treatment consisted of 35 cuttings. The irradiated cuttings were then planted into a perlite medium and after 60 days, the number of survived cuttings, the number of new leaves and shoots, the length of new shoots and days to flower bud emergence were measured. The survival rate of cuttings decreased as the dose of radiation increased. The highest mean survival rate was 97% obtained from the non-irradiated cuttings (0 Gy) followed by 89% from 10 Gy, 94% from 20 Gy, 69% from 40 Gy, 54% from 60 Gy and 31% from 80 Gy and only 9% survival at 100 Gy. Higher radiation rates also decreased the leaves and shoot numbers, shoot length and fluorescent emergence. Based on the survival rate graph, the lethal dose 50% (LD50) value was 59 Gy. The results revealed that gamma irradiation had various effects on the growth of G. pulchella including vegetative and flower development. The value of LD50 will be used to determine the optimal effective dose for further radiation-induced mutation in G. pulchella research.