Efficient Plant Regeneration via Indirect Organogenesis in Carnation (Dianthus caryophyllus semperflorens flore pleno) Cultivars

Callus induction and plant regeneration are important steps of in vitro plant breeding of ornamental plants. In this study, the effects of different combinations of plant growth regulators (PGRs), promoters, and minerals on callus induction and plant regeneration in different carnation cultivars were studied in a completely randomized design with three replications. For callus induction, 16 different combinations of 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BA), 1-naphthaleneacetic acid (NAA), and casein hydrolysate (CH) were studied using in vitro leaf explants. The Murashige and Skoog (MS) medium supplemented with 0.2 mg·dm⁻³ of 2,4-D and 200 mg·dm⁻³ of CH showed the highest frequency of callus induction. Among the cultivars, ‘Noblesse’ showed the highest rate of callus induction (91.67%). Regarding regeneration, BA, NAA, silver nitrate (AgNO₃), and adenine hemisulfate (As) were used in ten different combinations. The ‘Cameron’, ‘Tabasco’, and ‘Noblesse’ cultivars with 95.24% regeneration percentage showed the highest rate of plant regeneration. Generally, in most cultivars, the highest regeneration rate and shoot number per explant were found in the MS medium supplemented with 3 mg·dm⁻³ of BA, 0.6 mg·dm⁻³ of NAA, 5 mg·dm⁻³ of AgNO₃, and 40 mg·dm⁻³ of As. According to the results, the highest regeneration frequency was obtained when 40 mg·dm⁻³ of As was added to the medium. Finally, the flow cytometry analysis indicated that there were no significant differences between in vitro regenerated and control plants in terms of DNA ratios.