In vitro regeneration of chrysanthemum (Dendranthema grandiflora Tzvelev)

Abstract

In vitro direct regeneration without a callus intermediary is a pre-requisite for developing efficient transformation system, in ornamental crops including chrysanthemum (Dendranthema grandiflora Tzvelev) which is one of the popular flower crops of the world. An experiment was conducted to develop an efficient direct regeneration protocol for chrysanthemum. The surface sterilized shoot tip and leaf explants of cvs. Ravikiran and Chandrika were cultured on Murashige and Skoog medium fortified with different concentration of BAP (0.2-2.5 mg/1), Kinetin (0.2-2.5 mg/1), IAA (0.1-1.0 mg/1) and NAA (0.5-1.0 mg/1). The MS medium supplemented with 0.2 mg/1BAP or Kinetin+0.1 mg/1 was found best for obtaining maximum frequency of regeneration. Puncturing the surface sterilized explants before inoculation increased the frequency of regeneration from leaf explants. The number of regenerated adventitious shoots obtained was significantly more from cv. Ravikiran when compared to cv. Chandrika. Histological studies conducted showed that direct shoot regeneration was obtained from the mesophyll cells. The histochemical studies carried out revealed that arising shoot primordial, leaf primordial and pro-vascular stands showed intense protein and nucleic acid content. Preliminary studies on Agrobacterium mediated genetic transformation revealed that chrysanthemum transformants with Kanamycin after a co-cultivation period of 48 hours.