Micropropagation of Dianthus gratianopolitanus

Meristem culture and/or thermotherapy were used to eliminate viruses from ornamental Dianthus gratianopolitanus Vill. ('Spotti' and 'Frosty Fire') mother plants. Shoot tip, leaf, node, and ovary explants collected from greenhouse-maintained, virus-free plants were cultured in vitro for shoot initiation on Murashige and Skoog (MS) medium containing BAP, kinetin, or 2-iP with or without IAA or NAA. Culture of shoot tips in MS with 0.57 μM IAA and node explants in MS with 2.46 μM 2-iP is recommended for 'Spotti' cultivar. In 'Frosty Fire', optimum number of axillary shoots was obtained from shoot tip and node explants in MS without plant regulators. Leaves and ovaries were not adequate explants for D. gratianopolitanus micropropagation because none or only a low percentage of explants regenerated shoots. High levels of cytokinins increased the number of shoots per explant but also increased the production of aberrant phenotypes and induced hyperhydricity. Adventitious shoots rooted in vitro with auxins, but maximum rooting was 97% ex vitro without auxins. This study demonstrated that D. gratianopolitanus can be successfully micropropagated. Chemical names used: 6-benzyladenine (BAP); kinetin (KIN); 6-(γ,γ-dimethylallylamino)-purine (2iP); indole-acetic acid (IAA); indole-3-butyric acid (IBA); α-naphthaleneacetic acid (NAA); gibberellic acid (GA₃).