Radiation induced mutagenesis studies in Zinnia species

Abstract

Zinnia elegans is a herbaceous annual with diverse flower colours, flower types and plant height. The commercial value of ornamental plants lies in the superior and novel traits. One of the techniques to develop plant varieties with superior traits is to induce mutations using gamma radiation to obtain novel traits the seeds of Zinnia elegans var Dreamland were treated with 10, 20, 50, 75, 100, 125, 300, 400 and 500Gy doses of gamma radiation. The success of induced mutagenesis technique using gamma rays in any crop or ornamental plants lies in the determination of optimum dose (LD50). The LD50 for % germination was found to be 176.51Gy. The results pertaining to the effect of gamma radiation on seedling growth showed that there was significant decline in the seedling growth as compared to the control. Three doses of gamma radiation (75Gy, 100Gy and 125Gy) were selected to obtain new and novel varieties of Zinnia elegans var. Dreamland and significant variations in morphological characteristics such as plant height, leaf length, flower diameter, number of flowers and number of ray florets was observed. The radiation dose 125Gy was found to be effective in the production of variation in Zinnia elegans. The analysis of polymorphism using RAPD markers showed that the mutants were distinct among them and the control plant. Zinnias are propagated by seeds and there is a high tendency for the mutant plants to decline in the production of seeds. To overcome the disadvantage in vitro culture technique for Zinnia was established using growth regulators. 0.3mg/L BAP was found to be effective in producing multiple buds and the root formation was efficient in MS media without growth regulators newline