Hamidreza Sabaghi - Department of Horticultural Science, Agriculture and Natural Resources, University of Hormozgan, Bandar Abbas, Iran
Gholamreza Sharifi-Sirchi - Department of Biotechnology Engineering, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran
Pejman Azadi - Department of Genetic Engineering, Agricultural Biotechnology Research Institute of Iran (ABRII), Karaj, Iran
Mohamad Hossein Azimi - Ornamental Plants Research Center (OPRC), Horticultural Sciences Research Institute (HSRI), Agricultural Research, Education and Extension Organization (AREEO), Mahallat, Iran

The present study has been designed and executed to determine the best growth-regulating compound for callus induction as well as to specify the optimum dose of gamma irradiation in carnation cultivars (Tabasco, Nobless, Cameron, Tabor, Eskimo, and Mariposa). In this experiment, an MS culture medium was used to evaluate the various levels of growth regulator concentrations including NAA in four levels (۰, ۰.۵, ۱, and ۲ mgl-۱), ۲,۴-D in five levels (۰, ۰.۵, ۱, ۲, and ۳ mgl-۱), and BA in two levels (۰.۵ and ۱ mgl-۱). Irradiating the callus of leaf explants was carried out three weeks after cultivation at ۰, ۱۵, ۲۵, ۳۵, ۴۵, and ۵۵-gray doses-to determine the optimum dose of gamma radiation. The analysis of data and illustration of graphs were carried out via Excel software and according to the obtained results, the radiation level that killed ۵۰% of the calluses was selected as the optimum dose for further experiments. The results have indicated that all main effects and the interaction effects regarding the characteristics of callogenesis percentage and callus volume were significant at a probability level of ۱%. Means were grouped using Duncan's multiple range test, revealing that the highest level of callus induction was in Eskimo cultivar with a ۷۳% overall mean. Overall, the results indicate that ۲ mgl-۱ ۲,۴-D, ۰.۵ mgl-۱ BA is the best regulatory compound for callogenesis in carnation cultivars. Moreover, it was found that on average, the ۲۵-gray dose leads to suitable results in the callus explants of all cultivars. 

callus induction, carnation, PGRs, In vitro mutagenesis, Mutation breeding