ISHS Acta Horticulturae 630: XXVI International Horticultural Congress: Nursery Crops; Development, Evaluation, Production and Use
EFFECTS OF THIDIAZURON AND NUTRIENT SALT FORMULATIONS ON MICROPROPAGATION OF HARDY HIBISCUS (HIBISCUS MOSCHEUTOS L.) |
| Authors: | T. West, J.E. Preece |
| Keywords: | axillary shoot proliferation, cytokinin, DKW, floriculture, nutrient salts, TDZ |
| Abstract:
Hardy hibiscus has been gaining in popularity as a landscape plant. Effects of thidiazuron (TDZ) concentrations and nutrient salt formulations were studied on two H. moscheutos hybrids; ‘Lord Baltimore’ (cutting propagated cultivar) and ‘Southern Belle’ (seed propagated cultivar) to produce an efficient in vitro axillary shoot proliferation protocol for micropropagation. Six TDZ concentrations (0, 10-9, 10-8, 10-7, 10-6, or 10-5 M) were compared to determine which would stimulate the proliferation of the most viable axillary shoots. Also, five nutrient salt formulations (MS, ½ Macro MS, WPM, LP, or DKW) representing different salt formulations (low, intermediate, and high) were studied to determine a suitable nutrient medium formulation for axillary shoot proliferation. The best treatment tested for axillary shoot proliferation of the two H. moscheutos hybrids was the DKW medium (high salt formulation) with 10-7 M TDZ. After 16 weeks on this medium, there were 3.1 shoots on the initial nodal explants, and 5.5 nodes separated by sufficient internode length for subculturing. Thidiazuron concentrations higher than 10-7 stimulated shoot proliferation but the shoots did not elongate well and were very chlorotic with subsequent shoot tip dieback. Thidiazuron concentrations lower than 10-7 M stimulated little to no shoot proliferation. Explants growing on MS, ½Macro MS, and WPM did not proliferate axillary shoots rather the primary shoot elongated with no branching. Explants on LP medium (medium salt formulation) proliferated shoots but the shoots were not as vigorous as those on DKW (high salt formulation). | |
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