Mechanisms generating the numerous hues of chrysanthemum petals can be traced to in vitro γ-ray-induced mutagenesis.

In terms of global cut flower production, chrysanthemum (Dendranthemum grandiflorum kitam.) ranks among the top ten. When a plant species possesses colour characteristics associated with those of ancestral species, that colour is described as being white, yellow, or pink, with white coloration representing an absence of pigments, and yellow and pink coloration each represents the presence of carotenoids and anthocyanins, respectively. Pigments, or a combination of pigments, have been improved upon to provide an expansive rainbow of floral colours like orange, dark red, purplish-red, and red. Recent green-flowered varieties have developed a reputation for containing chlorophylls in their ray petals. Additionally, transgenic interventions have been used to breed violet/blue flowers. Flower colour is a highly regarded characteristic of any flower cultivar, particularly chrysanthemum. Breeders' ultimate goal is to create newer chrysanthemum cultivars with innovative characteristics, such as new flower colours, using a time and input-efficient approach. Investigating the molecular mechanisms that regulate flower pigmentation may yield critical insights into the rational manipulation of floral colour. To generate a diverse array of flower colour mutants in chrysanthemum cv. “Candid” through mutagenesis, in vitro grown micro shoots were exposed to 10, 20, 30, and 40 Gy gamma irradiation at 100 Gy per minute and were evaluated for different parameters. The rhizogenesis parameters declined with the increase in irradiation dose from 0 Gy to 40 Gy, while as, 10 Gy dose proved to record minimum decline in contrast to the control. Survival, leaf size, and the number of leaves plant-1 after the 8th-week interval exhibited a downward trend with the increasing trend of gamma irradiation dose but recorded a least drop in plants raised from shoots irradiated with 10 Gy gamma irradiation dose with respect to the control. Apparently, the minimum delay in the number of days to floral bud appearance took under 10 Gy compared to control. The highest number of flower colour mutants was recorded under 10 Gy (light pink, orange-pink, white and yellow). Demountable mutation frequency based on flower colour was desirable in plants irradiated with the slightest dose of 10 Gy.