Improved Adventitious Shoot Organogenesis and Callus Production from Leaf Explants of Petunia hybrida L. by Benzyladenine (BA) and Naphthalene Acetic Acid (NAA)

Petunia (Petunia hybrida) is an ornamental plant species of high economic potential. One of the appropriate methods for propagation and breeding of petunia is tissue culture. This experiment was conducted to investigate the effects of different concentrations of benzyl adenine (BA) either alone or in combination with different concentrations of naphthalene acetic acid (NAA) on the regeneration of adventitious shoots and callus production in Petunia hybrida. For the regeneration of adventitious shoots and callus production, leaf segment explants taken from germinated seeds were cultured on MS basal media supplemented with different concentrations of BA (0.1, 0.4, 0.8 mg L-1) solely and/or in combinations with and NAA (0, 0.1, 0.2 and 0.4 mg L-1). Cultures were incubated under dark conditions for two weeks and then transferred to light condition. After 20 days of keeping in the light condition, the results showed that BA and NAA had significant effect on shoot regeneration. When BA applied alone, the lowered concentrations were effective in shoot regeneration, however when used in combination with NAA, its increased concentrations were more suitable. The greatest percentage of shoot regeneration was recorded in the medium with high level of BA to NAA. The highest number and fresh weight of shoots (18 shoots per explant) were obtained in MS medium supplemented with 2 mg L-1 BA + 0.4 mg L-1 NAA. The greatest shoot length (5.1 cm) was obtained in MS medium containing 0.5 mg L-1 BA + 0.2 mg L-1 NAA. Also, the greatest callus fresh weight was observed in MS medium supplemented with 0.5 mg L-1 BA + 0.4 mg L-1 NAA. Therefore, MS medium supplemented with 2 mg L-1 BA combined with 0.4 mg L-1 NAA could be suggested for direct shoot regeneration and large scale propagation of petunia from leaf explants.