Mass propagation of Dendrobium ‘Zahra FR 62’, a new hybrid used for cut flowers, using bioreactor culture

Abstract

A mass propagation protocol for Dendrobium ‘Zahra FR 62’, the result of hybridization between Dendrobium ‘Sonia Deep Pink’×Dendrobium 1265, was successfully established. Half-strength Murashige and Skoog (MS) medium containing 1mg/L thidiazuron (TDZ) and 0.5mg/L N6-benzyladenine (BA) resulted in high protoccorm-like body (PLB) formation and initial proliferation of Dendrobium using shoots as the donor explant via repeated subcultures. High proliferation and optimal growth of PLBs was possible by culturing PLBs in a 3-L bioreactor with 10 vessel volumes per minute (vvm) (CS-9) containing half-strength MS medium with 0.05mg/L BA (M-2). A total of 807.7 PLBs formed with an average of 247.5 new PLBs per subculture. The culture system was improved by adding 15g of explant to 5vvm of dissolved oxygen, although good quality PLBs formed when 10g of explant was combined with 10vvm of dissolved oxygen. PLBs converted into healthy plantlets by culturing them on half-strength MS containing 0.05mg/L BA. Thereafter, germinated PLBs were subcultured on half-strength MS medium with full vitamins and free of plant growth regulators (RM-1). Rooted plantlets were successfully acclimatized ex vitro with 90–100% survival using Cycas rumphii bulk and grew well after repotting individually into a mixture of C. rumphii bulk and wood charcoal (1:1, v/v).