USING SSR MARKERS TO CORRECTLY IDENTIFY HYDRANGEA GERMPLASM, ASSESS PARENTAGE, AND VERIFY HYBRIDS

Popularity and use of Hydrangea 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. anomala, and H. quercifolia are also widely cultivated. In addition to species diversity, there is high intraspecies variation, particularly in H. macrophylla which includes two cultivated subspecies, mophead and lacecap inflorescence forms, French, Japanese, dwarf, and variegated varieties. Relatively little is known about the genetic background or combinability of these plants. Recently a molecular key for Hydrangea species was established and used to resolve taxonomy at the species level. Here microsatellite markers are used to verify interspecific hybrid between H. aspera and H. involucrate, 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 enhance plant patent applications.