Main content area

Using SSR Markers to Estimate Diversity Among Hydrangea Germplasm and Improve Breeding of New Cultivars

Rinehart, Timothy, Reed, Sandra M.
Acta horticulturae 2010 no.885 pp. 291
Hydrangea macrophylla, Hydrangea paniculata, Hydrangea arborescens, Hydrangea anomala, Hydrangea quercifolia, germplasm, ornamental plants, species diversity, genetic variation, genetic markers, DNA fingerprinting, interspecific hybridization, hybrids, parentage, cultivars, plant breeding, cultivar identification, taxonomy
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. 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. We recently established a molecular key for Hydrangea species and used it to resolve taxonomy at the species level. We used the same SSR markers to verify interspecific hybridization within Hydrangea and confirm intergeneric hybrids between Dichroa and Hydrangea. Here we use 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 enhance plant patent applications.