Diversity in nuclear DNA content and ploidy level of Hedychium species and hybrids

ABSTRACT

Hedychiums are multipurpose plants cultivated as ornamentals because of their multicolor and showy and scented flowers and as medicinal plants because of their essential oils that have been found to possess antimicrobial and insecticidal properties. There is often taxonomic and botanical confusion about Hedychium species and cultivars because of the apparent existence of more than one cytotype within several Hedychium species, most likely because of the ease with which these species hybridize. Nuclear DNA content (2C-DNA) was determined for the first time in 23 Hedychium species and hybrids. The 2C-values ranged from 1.70 pg to 3.98 pg. We also determined the chromosome number of one species, Hedychium stenopetalum, which was found to be diploid (2n = 2x = 34), supporting the widely held view that the basic chromosome number in Hedychium is x = 17, and the existence of different cytotypes is most probably attributable to natural hybridization. Our results should be helpful not only in clarifying the botanical and taxonomic confusion in Hedychium but also in paving the way for a sound breeding program for this increasingly important ornamental ginger.

KEYWORDS:

• Chromosome number
• DNA content
• genome size
• ginger lily
• ornamental ginger

Acknowledgments

We are grateful to Jeff S. Kuehny, Department of Horticulture, Louisiana State University, Baton Rouge, LA; Dave Creech and Dawn Parish Stover, SFA Arboretum, Stephen F. Austin State University, TX; Hayes Jackson, Anniston, AL; and Tom Wood, Gainesville, FL, for providing some of the Hedychium plant material. We also thank Kermis Myrick, Carrie Witcher, and Alexandria Goins for maintaining the plants in the greenhouse and processing the plant samples.

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