Submitted to: Southern Nursery Association Research Conference
Publication Type: Proceedings
Publication Acceptance Date: August 10, 2006
Publication Date: December 15, 2006
Citation: Jones, K.D., Reed, S.M. and Rinehart, T.A. 2006. Wide crosses in the Hydrangeaceae: Dichroa febrifuga x Hydrangea macrophylla. Proceedings of the Sourthern Nursery Association Research Conference. 51:577-579. Interpretive Summary: Hydrangeas are among the most popular flowering shrubs, with annual U.S. sales of approximately $32 million. Their popularity is likely to increase in the future, especially if new and improved cultivars are introduced into the marketplace. This study reports the successful hybridization of Hydrangea macrophylla with Dichroa febrifuga, a closely related species with flowers that remain blue in the absence of aluminum and persistent, metallic-blue fruit. This work represents the first step towards incorporating these two ornamental traits into H. macrophylla.
Technical Abstract: Both Hydrangea macrophylla and Dichroa febrifuga are members of the family Hydrangeaceae. Previous phylogenetic studies have found H. macrophylla to be more closely related to D. febrifuga than to other members of the genus Hydrangea. Blue flower color is the most desirable trait of H. macrophylla; however, blue flowers are produced only if adequate aluminum is available to the plant. In contrast, we have observed blue flowers on D. febrifuga plants grown in the absence of aluminum. While H. macrophylla has ornamental appeal only while inflorescences are present, D. febrifuga produces persistent, metallic-blue fruit that provide winter interest. The objective of this study was to hybridize the two species to incorporate these two ornamental traits from D. febrifuga to H. macrophylla. Reciprocal crosses were made between D. febrifuga (UBC Garden form) and diploid (‘Veitchii’) and triploid (‘Taube’) cultivars of H. macrophylla. Approximately one-third of the seed capsules were harvested 9 to 10 weeks after pollination and embryo rescue via ovule culture employed. The rest of the capsules were allowed to mature on the plant and seed germinated in the greenhouse. Both triploid and diploid H. macrophylla cultivars successfully hybridized with D. febrifuga and reciprocal hybrids were obtained from both H. macrophylla parents. Hybrids were obtained using both ovule cultures and seed germination. Hybridity was verified using eight SSR markers. Hybrids are healthy and vigorous and will be evaluated for ornamental traits and fertility.