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'Appalachian Spring': A New Flowering Dogwood Cultivar Resistant to Dogwood Anthracnose

W.T. Witte, M.T. Windham, E. Graham and R.N. Trigiano

Tennessee Agricultural Experiment Station, Knoxville, TN 37901-1071

A paper from the Proceedings of the 10th Metropolitan Tree Improvement Alliance (METRIA) Conference held in St. Louis, MO, September 30 and October 1, 1998, co-sponsored by the Landscape Plant Development Center and the Society of Municipal Arborists.

Abstract

'Appalachian Spring' is a new white-bracted Cornus florida cultivar with upright growth habit and prolific blooming. The parent tree was found growing wild in heavily shaded forest understory on Catoctin Mountain in Maryland. It was propagated and clonal plants were challenged for disease resistance to dogwood anthracnose. Two trees grown from cuttings in 1990 were transplanted to the field in 1994. They have grown to 2.3 m (8.5 ft) tall x 1.7 m (5.5 ft) wide and have a trunk caliper of 4 cm (1.6 in). Mean inflorescence number per tree was 194 in 1996 and 299 in 1997. Mean bract length of 100 inflorescences was 7.1 cm (2.8 in) for the largest pair of bracts (typically the inner pair of bracts that immediately subtend the receptacle). Bracts are not overlapping as in 'Cloud 9' and are not presented in a flat plane, but have a gently curving sculptural aspect.

Leaves of 'Appalachian Spring' are apple green with lighter venation, turning to bright red in autumn. The abundant berries are bright red. Leaf size is strikingly larger than most other flowering dogwood cultivars. When we compared the largest leaves on one-year budded liners of 'Appalachian Spring' to the largest leaves on 'Cherokee Brave' liners, a vigorous cultivar with large leaves, the former averaged 9.6 cm (3.8 in) wide x 17.4 cm (6.9 in) long and the latter averaged 8.1 cm (3.2 in) wide x 14.2 cm (5.6 in) long.

'Appalachian Spring' has demonstrated unusual resistance to dogwood anthracnose caused by Discula destructiva. Independent tests for disease resistance were completed in 1992 and 1996 by the Tennessee Agricultural Experiment Station at Ozone, Tennessee and by the U.S. Forest Service at Bent Creek in western North Carolina. In the 1992 test, the Forest Service screened thousand of dogwoods for resistance and 'Appalachian Spring' was the only one to survive the trial.

DNA fingerprints were developed for 'Appalachian Spring' and compared with fingerprints of 'Cloud 9', 'Springtime', 'Fragrant Cloud', 'Cherokee Princess' and 'Cherokee Daybreak'. Five distinctive markers for 'Appalachian Spring' were identified. Using Principle Coordinate Analysis, 'Appalachian Spring' was placed well outside the cluster of the other white dogwood cultivars.

Since 'Appalachian Spring' was found wild, it cannot be patented. However, the words 'Appalachian Spring' for use as a dogwood cultivar name and the use of the word 'Appalachian' as a prefix for a series of dogwood cultivars from the Tennessee Agricultural Experiment Station can be trademarked.

Release and marketing of 'Appalachian Spring' is being handled through Tennessee Advanced Genetics, Tennessee Foundation Seed, Inc. and the Tennessee Crop Improvement Association, all at 2640-C Nolensville Road, Nashville, TN 37211 (615.242.0467). Current supplies are limited and are being increased. The 'Appalachian Spring' cultivar will give the nursery and landscape industry a new and improved dogwood that can be marketed in areas where dogwood anthracnose is now endemic.


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