|Rajasekaran, Kanniah - Rajah|
Submitted to: Extension Publications
Publication Type: Abstract Only
Publication Acceptance Date: 10/2/2008
Publication Date: 10/2/2008
Citation: Sakhanokho, H.F., Kelley, R.Y., Rajasekaran, K., Tabanca, N., Sampson, B.J., Wedge, D.E. 2008. Breeding Hedychium Species, Ornamental Ginger Plants with Insecticidal and Anti-Microbial Activities. Extension Publications.
Technical Abstract: Hedychium species belong to the ginger family with great potential as ornamentals, but lodging is an impediment to this possibility, so there is a need for more compact Hedychium cultivars. Hedychium muluense (diploid) is one of the few dwarf species, but it is not ornamentally as attractive as some of the taller and tetraploid cultivars/species. Therefore, the first goal of this investigation was to induce polyploidy, in particular tetraploidy in H. muluense to remove the ploidy hybridization barrier. The second objective was to assess the insecticidal and antimicrobial activities of essential oils and crude leaf and rhizome extracts from selected Hedychium species/cultivars. Polyploidy was successfully induced in the diploid H. muluense (2n = 34) by treating embryogenic callus with various concentrations of colchicine (2.5, 5, or 10 mM) or oryzalin (30, 60, or 120 µM) for 24, 48, or 72 hours. Flow cytometry, chloroplast number, and stomatal frequency and size were used to assess the ploidy level of the regenerated plants. Triploids, tetraploids, and mixoploids were obtained with both antimitotic agents. The most efficient treatment for inducing tetraploidy was the 2.5 mM colchicine for 24 hours. The essential oils from selected Hedychium species/cultivars were very effective against the azalea lace bug (Stephanitis pyrioides), Aspergillus flavus [an aflatoxin (carcinogen) producing fungus], Aspergillus parasiticus, Verticillium dahlieae, Fusarium verticillioides (formerly F. moniliforme). The crude leaf extracts showed more antibacterial (against E. coli) and antifungal (against A. flavus) effects than the rhizome extracts.