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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETICS, GENETIC IMPROVEMENT, AND IMPROVED PRODUCTION EFFICIENCY OF NURSERY CROPS

Location: Floral and Nursery Plants Research Unit

Title: Resistance to rust in Hydrangea arborescens

Authors
item Li, Yonghao -
item Windham, Mark -
item Trigiano, Robert -
item Windham, Alan -
item Reed, Sandra
item Spiers, James
item Rinehart, Timothy

Submitted to: Southern Nursery Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 21, 2010
Publication Date: December 22, 2010
Citation: Li, Y., Windham, M., Trigiano, R., Windham, A., Reed, S.M., Spiers, J.M., Rinehart, T.A. 2010. Resistance to rust in Hydrangea arborescens. Southern Nursery Association Proceedings. 55:427-429.

Interpretive Summary: Smooth hydrangea, Hydrangea arborescens, is a deciduous shrub native to eastern North America. It is one of the most cold-hardy members of the genus. It flowers consistently each year and is not damaged by late spring freezes. In general, it is free of major disease and insect problems; however, it is often disfigured by rust in late summer and autumn. Seven H. arborescens selections (‘Annabelle’, ‘Frosty’, ‘Green Dragon’, ‘Hayes Starburst’, ‘Pink Pincushion’, ‘Ryan Gainey’ and ‘White Dome’) were examined for resistance to rust. Resistance was based on colony numbers and production of disease spores on leaf tissue of the seven cultivars under laboratory conditions. ‘Frosty’ was found to be more resistant to this disease organism than the other six cultivars. Identification of a source of resistance will assist in the development of rust-resistant smooth hydrangea cultivars.

Technical Abstract: Smooth hydrangea, Hydrangea arborescens, is a deciduous shrub native to eastern North America. With adaptability from USDA cold hardiness zones 3 to 9, it is one of the most cold-hardy members of the genus. Because it flowers on current year’s growth, smooth hydrangea blooms consistently each year and is not damaged by late spring freezes. In general, it is free of major disease and insect problems; however, it is often disfigured by rust in late summer and autumn. Seven H. arborescens selections (‘Annabelle’, ‘Frosty’, ‘Green Dragon’, ‘Hayes Starburt’, ‘Pink Pincushion’, ‘Ryan Gainey’ and ‘White Dome’) were examined for resistance to rust. Leaf disks were inoculated with spores of Pucciniastrum hydrangeae and colony number and spore production were determined 10 days after inoculation. ‘Frosty’ had significantly lower numbers of colonies and spores than the other six cultivars. This study provides initial information needed for breeding rust-resistant H. arborescens.

Last Modified: 9/20/2014
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