‘Rutpink’ (Scarlet Fire®) Kousa Dogwood

Authors: MOLNAR, THOMAS - Rutgers University; MUEHLBAUER, MEGAN - Rutgers University; Wadl, Phillip; CAPIK, JOHN - Rutgers University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2017
Publication Date: 11/8/2017
Citation: Molnar, T.J., Muehlbauer, M., Wadl, P.A., Capik, J.M. 2017. ‘Rutpink’ (Scarlet Fire®) Kousa Dogwood. HortScience. 52(10):1438-1442. https://doi.org/10.21273/HORTSCI12242-17.
DOI: https://doi.org/10.21273/HORTSCI12242-17

Interpretive Summary: The value of dogwoods as a deciduous flowering tree species exceeds $30 million annually. The most economically valuable and widely produced dogwoods for the nursery and landscape industry are the large-bracted species, which include flowering dogwood, kousa dogwood, and their interspecific hybrids. These deciduous trees are highly valued for their spring display of pink, red, or white bracts, brilliant red autumn foliage, and exfoliating bark. Large-bracted dogwoods are widely grown throughout mid-temperate regions of eastern North America, both in the wild and as coveted ornamental trees in urban and suburban landscapes. Across this range, flowering dogwoods have been severely affected by two diseases: dogwood anthracnose and powdery mildew. The breeding program at Rutgers University has been active for over 40 years and focuses on interspecific hybridization of dogwoods, with the goal of combining the best traits of both species in novel cultivars. Kousa dogwood is much more tolerant to anthracnose and powdery mildew than flowering dogwood. Hybrids between these species are generally more vigorous than either parent and have shown resistance or tolerance to anthracnose and powdery mildew. As such, the Rutgers interspecific dogwood hybrids have had a significant impact on the market for large-bracted dogwoods. The goal of researchers at Rutgers and an USDA-ARS scientist was to develop and release ‘Rutpink’ (Scarlet Fire®) a new kousa dogwood cultivar. ‘Rutpink’ exhibits a moderately vigorous, upright growth habit with dark-green foliage and, most notably, large, dark-pink floral bracts. It has also shown strong field tolerance to the pathogens causing dogwood anthracnose and powdery mildew. Trees of ‘Rutpink’ have exhibited no winter injury under field tests in New Brunswick, NJ, in Zone 7a (0°F – 5°F). The new cultivar was derived from the open pollination of an unreleased kousa dogwood seedling (Rutgers K187-44) held in the Rutgers germplasm collection. A parentage analysis using DNA markers was conducted to identify its male parent from a pool of 28 potential contributors and results identified the breeding selection Rutgers KN123-6. ‘Rutpink’ adds to genetic diversity in the landscape beyond what has been released from Rutgers previously.

Technical Abstract: ‘Rutpink’ is a new kousa dogwood (Cornus kousa) cultivar released from the woody ornamentals breeding program of the New Jersey Agricultural Experiment Station (NJAES) and Rutgers University and marketed under the name Scarlet Fire® dogwood (Fig. 1). It exhibits a moderately vigorous, upright growth habit with dark-green foliage and, most notably, large, dark-pink floral bracts (Fig. 2). It has also shown strong field tolerance to the pathogens causing dogwood anthracnose (Discula destructiva) and powdery mildew (primarily Erysiphe pulchra). Trees of ‘Rutpink’ have exhibited no winter injury under field tests in New Brunswick, NJ, in Zone 7a [0ºF – 5ºF (United States Department of Agriculture, 2012)]. ‘Rutpink’ was derived from the open pollination of a C. kousa seedling (Rutgers K187-44) held in the Rutgers germplasm collection. A parentage analysis using nine single sequence repeat (SSR) markers was conducted to identify its male parent from a pool of 28 potential contributors; results identified the breeding selection Rutgers KN123-6.