Induction of Onion (Allium cepa L. cv. Granex 33) Callus Formation and Embryogenesis

Abstract

The comparative study on growth and differentiation between basal portion and bulb scale of onion (Allium cepa L cv. Granex 33) grown on different culture media were carried out. The results showed that the basal plate tissue cultured on Murashige and Skoog medium (MS) containing 1.0-1.5 mg/I 2,4-dichlorophenoxy acetic acid (2,4-D) and on modified MS medium containing 3.3 mg/1 3,6-dichloro-o-anisic acid (Dicamba) was remarkedly induced to form a compact callus within 6 weeks after culture initiation. However, embryogenesis has been generated only from the callus mediated directly on MS medium containing 1.0 mg/I 2,4-D and subsequently cultured on MS medium comprising 0.1 mg/1 indole-3-acetic acid (IAA) and 1.0 mg/I 6-benzylaminopurine (BAP) within 15 weeks. After transferring onto MS medium containing no growth regula¬tors the embryoid developed into complete plantlets within 8 weeks. In contrast to the basal portion tissue, the bulb scale tissue cultured on these media produced afriable callus which could not regenerate into complete plantlets.