Gamma irradiation effects on in vitro shoot cultures of Dianthus caryophyllus L. and molecular characterization of mutants using ISSR markers

The current investigation was carried out to study the effect of different doses of gamma irradiation on in vitro shoot cultures of carnation (Dianthus caryophyllus L.) and characterization of mutants using ISSR markers. The trial was undertaken at the experimental farm and laboratory of the Department of Floriculture and Landscaping, Dr. YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP). The experiment on ten carnation genotypes i.e. 7 mutants, 3 parents viz.; ‘Dark Rendezvous’, ‘Madras’ and ‘Tempo’ was laid out in Randomized Block Design (RBD) under polyhouse conditions. All the mutants developed after the irradiation with gamma rays showed variation in color. In this study, different morphological parameters of the mutants and their parents were recorded. Among different mutants, maximum plant height was recorded in mutant of ‘Dark Rendezvous’ i.e. ‘Rendez-Vous A2’ (67.70 cm) and maximum flower size in ‘Rendez-Vous C2’ (8.40 cm). Duration of flowering was recorded maximum in ‘Tempo A1’ (67.67 days) and vase life in ‘Rendez-Vous C1’ (14.79 days). For the majority of the characters analyzed, all mutants performed better in comparison to parents. Moreover, for the characterization of mutants at the molecular level, ten ISSR primers were used and DNA polymorphism was observed with four primers. A total of fifteen polymorphic bands were produced by these four primers. No monomorphic band was observed with any primer resulting in 100% polymorphism. Variations in the plant material can be explained through genetic polymorphism. These results directly strengthen the significance of mutation breeding in developing improved carnation cultivars and substantiate the use of molecular characterization for validating genetic variation. Furthermore, they emphasize the scope for the commercial expansion of carnation cultivation through the selection of promising mutants.