Induction of novel variants in Chrysanthemum morifolium through electron beam radiation

Un-rooted cuttings of chrysanthemum varieties Pusa Chitraksha, Pusa Anmol and Basanti were treated with Electron Beam (EB) radiation (20 Gy and 30 Gy) with an objective of inducing variability and evaluated at 1CAR-DFR, Pune during 2020. A gradual and significant reduction in vital plant growth parameters was observed with increase in doses. Influence of EB radiation (at 30Gy) on plant height (-34.55%), plant spread (-28.60%), intemodc length (-39.04%), leaf length (-26.95%), leaf width (-29.28%), number of flowers per plant (-23.28%) and for flower diameter (-24.80%) in comparison to control was recorded. Delay in days to bud initiation and flowering at higher dose (30 Gy) were 13.47 days and 17.33 days, respectively over control. Among the varieties, Pusa Chitraksha was found superior for most of the vegetative growth and flowering parameters. However, it exhibited delay in bud initiation (95.80 days) and flowering (118.0 days). The trend is similar for other two varieties at higher dose. In the interaction effect (Variety x EB dose), plant height (17.00 cm) was very less in variety Basanti at 30 Gy dose. Flower diameter (3.26 cm) was reduced with increased EB dose (30 Gy) in Pusa Aditya compared to control (5.24 cm). Pusa Chitraksha exhibited variation in flower colour (Magenta to white/ cream colour) and Pusa Aditya produced red colour flower at 30 Gy. Based on the study, it can be inferred that Electron Beam at 20-30 Gy had potential to create variation in chrysanthemum.