In vitro regeneration and somaclonal variation of Petunia hybrida

The effect of different levels of naphthaleneacetic acid (NAA) and benzyladenine (BA) on shoot multiplication and regeneration of Petunia hybrida was studied. Regenerated shoots from leaf explants were grown ex vitro for analysis of somaclonal variation. Seeds of Petunia hybrida were germinated in vitro on MS basal medium. The seedlings were used as a source of explants for the multiplication and regeneration experiments. For the shoot multiplication experiment, shoot explants taken from germinated seedlings were cultured on MS basal media supplemented with different concentrations of BA (0.1, 0.4, 0.8 mg l ―1 ) and NAA at concentration of 0.1 mg l ―1 . Highest number of axillary shoot was obtained on medium supplemented with 0.8 mg l -1 BA and 0.1 mg l ―1 NAA. For regeneration experiments, leaf sections taken from germinated seedlings were cultured onto MS media supplemented with three levels of BA (0.5, 1.0 and 2.0 mg l ―1 ) and 0.5 mg l ―1 NAA. The highest shoot regeneration rate (45%) was observed in MS medium supplemented with 2 mg l ―1 BA. For the evaluation of somaclonal variation, lateral bud explants were taken from pink colored petunia plants that were grown in the greenhouse. The buds were disinfected and cultured on MS basal media supplied with 30 mg l ―1 gentamycin sulfate and 30 mg l ―1 Benlate. After shoots grew, leaf sections were then taken from them shoots and cultured onto shoot regeneration medium (MS medium supplemented with 2 mg l ―1 BA). The regenerated adventitious shoots were cultured on MS medium without growth regulator. These shoots were then rooted, acclimatized and transferred to the greenhouse for evaluation. Two forms of leaf shape (orbicular and elliptic) and three flower colors (violet, purple and light pink) appeared on the plantlets.