Submitted to: International Symposium on Woody Ornamentals of the Temperate Zone
Publication Type: Abstract Only
Publication Acceptance Date: May 26, 2008
Publication Date: May 26, 2008
Citation: Rinehart, T.A., Reed, S.M. 2008. Using SSR Markers to Estimate Diversity Among Hydrangea Germplasm and Improve Breeding of New Cultivars. International Symposium on Woody Ornamentals of the Temperate Zone pg 72. Technical Abstract: Hydrangea popularity and use in the landscape has expanded rapidly in recent years with the addition of remontant varieties. Most cultivars in production belong to the species Hydrangea macrophylla but H. paniculata, H. arborescens, H. aspera, H. heteromalla, H. integrifolia, H. anomala, H. seemanii and H. quercifolia are also commercially available. In addition to species diversity there is high intraspecies variation, particularly in H. macrophylla which includes two subspecies, mophead flower types, lacecap flowers, French, Japanese, dwarf, and variegated varieties. Relatively little is known about the genetic background or combinability of these plants. We recently established a molecular key for Hydrangea species and used it to resolve the taxonomy of wild-collected germplasm. We used the same SSR markers to verify interspecific hybridization within Hydrangea and confirm intergeneric hybrids between Dichroa and Hydrangea. We have also used microsatellite markers to determine the parentage of new H. macrophylla cultivars such as 'Midnight Duchess', 'Blushing Bride' and 'Queen of Pearls', to identify mislabeled cultivars, to confirm the renaming of cultivars, and to demonstrate that some similar-looking cultivars are actually genetically unique. The same technology can be applied to "true to name" guarantees, plant labeling disputes, and be used to enhance plant patent applications.