In vitro approaches for chemical mutagenesis in carnation (Dianthus caryophyllus)

Horticultural Research, Hessaraghatta Lake Post, Bangalore 560 089(Received: June 2005; Revised: January 2006; Accepted: February 2006)Chemical mutagenesis is one of the major approachesfor induction of mutation [1]. Subjecting the minimumunit of explant· to mutagen can be achieved throughinduction of mutation under in vitro conditions of tissueculture where in pressure of diplontic selection is avoidedand the opportunity for the mutated cell to survive getsincreased [2]. Carnation (Dianthus caryophyllus) is amajor cut flower crop grown commercially worldwideand is easily amenable for tissue culture. This studyreports the effect of chemical concentration and theincubation duration of explant in mutagen on theirsurvival and growth response. The study is aimed atidentifying the right mode of mutagen application underin vitro condition. Two experiments were set up ofwhich the first one dealt with incubation of explant inmutagen before culturing where as the second approachwas incorporation of the mutagen into culturing mediaand subjecting the explant for mutageneis through-outthe growing period.Experiment 1: Incubation of explants in ethylmethane sulphonate (EMS): Nodes from in vitro shootletswere incubated in EMS at the concentrations of 0.1 %,0.5% and 1%. At each concentration explants wereincubated for 15, 30 and 60 minutes. To compare theeffect of mutagen, explants were incubated in distillwater at various duration and subsequently culturedand observed in comparison with mutagen treatedmaterial. All the treatments including control had sixreplications in each. Controls as well as the treatedexplants were cultured on Murashige and Skoog (MS)media [3] supplemented with 3% sucrose, 0.25mg/1BAP, 0.25mg/1 GA3, 0.1 mg/I NAA,