Induced Polyploidy and Mutagenesis of Embryogenic Cultures of Ornamental Ginger (Hedychium J. Koenig)

Hedychium J. Koenig is among the largest genera of Zingiberaceae. These plants are increasingly being used as ornamentals worldwide because of their diverse and showy, scented flowers. Hedychium plants are mainly planted in the landscape because they are generally too tall to be grown as potted plants. In 2004, a Hedychium breeding program was initiated at the USDA-ARS research station in Poplarville, Mississippi, where new and efficient tissue culture protocols were developed for micropropagation and other in vitro manipulations, including the induction of polyploidy and mutagenesis in selected cultivars and species. For example, polyploidy was successfully induced in several Hedychium hybrids and species, including H. bousigonianum, leading to the creation of dwarf forms of this species. Embryogenic calli from selected Hedychium species and hybrids were subjected to various concentrations of sodium azide (NaN3) and ethylmethanesulphonate (EMS) to induce mutations. H. muluense x 'White Starburst' calli treated with 20 mM NaN3 for 6 hours produced variegated plants. However, no variegation was obtained with EMS treatments. These in vitro assisted breeding techniques are accelerating the development of new and improved Hedychium cultivars.