Congenial In Vitro γ-Ray Induced Mutagenesis Underlying the Diverse Array of Petal Colours in Chrysanthemum ( Dendranthemum grandiflorum kitam ) cv. “Candid”

Chrysanthemum (Dendranthema grandiflorumkitam.) is a leading flower with applied value worldwide. Flower color is an important trait that influences the commercial value of chrysanthemum cultivars. Developing new chrysanthemum cultivars with novel characteristics, such as new flower colors in a time- and cost-efficient manner, is the ultimate goal for breeders. Understanding the molecular mechanisms that regulate flower pigmentation may provide important implications for the rationale manipulation of flower color. To generate a diverse array of flower color 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 decreased with the increase in irradiation dose from 0 Gy to 40 Gy, while a 10-Gy dose proved to record the minimum decline as compared to the control. Survival, leaf size, and the number of leaves on the plant−1 after the eighth week interval also decreased with the increasing trend of gamma irradiation dose but recorded a minimum decline in plants developed from shoots irradiated with a 10-Gy gamma irradiation dose, with respect to the control. The minimum delay in the number of days to floral bud appearance took under 10 Gy, as compared to control. The highest number of flower color mutants were recorded under 10 Gy (light pink, orange pink, white, and yellow). Amountable mutation frequency on the basis of flower color was desirable in plants irradiated with the smallest dose of 10 Gy.