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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. [ABSTRACT FROM AUTHOR]

Commercial blueberry production in the U.S. relies on cultivars derived from combinations of different blueberry species. Interspecific hybridization continues to be a vital strategy for blueberry breeding, especially in regards to improving abiotic and biotic stress tolerance to expand the range of production. Blueberry species have many different genome sizes, presumably due to differing ploidy levels and/or DNA content. In some species, such as Vaccinium corymbosum L. and V. pallidum Aiton, there are also different ploidy series available for breeding, further complicating the observed DNA content in elite selections. In this study we determined DNA content in 77 blueberry taxa including 11 species and 64 hybrid cultivars. Among these taxa are 11 diploid, 49 tetraploid, one pentaploid, and 16 hexaploid plants representing southern highbush, northern highbush, low bush, rabitteye, and half high blueberries. DNA content was measured for three separate tissue samples from at least three individual plants per taxa for accuracy. Absolute genome sizes varied significantly (P = 0.05) among ploidy levels, with 2C-value means of 1.09 pg for diploid, 2.10 pg for tetraploid, and 3.60 pg for hexaploid taxa. Holoploid genome size (2C DNA) was significantly correlated with ploidy or presumed chromosome number (2n) (r = 0.96, P = 0.0001) but only weakly correlated with monoploid genome size (1Cx-DNA) (r = 0.43, P = 0.0001). [ABSTRACT FROM AUTHOR]