Disease Resistant Roses
Roses are among the most important ornamental crops worldwide. In the United States alone, garden roses account for sales to 23,000,000 households. Sales of roses in 2014 in the United States generated $203.5 million, producing 36.6 million plants by 1,808 growers (U.S. Department of Agriculture, 2015). According to the Green Industry Research Consortium National Survey (Green Industry Research Consortium, 2013).
Roses accounted for 3% of overall sales from 18 different horticultural production crop categories. Rose industry sales equate to contributions to the U.S. economy of about $777 million. Most roses (65%) are sold through retail outlets, with the remaining 35% of rose sales coming from landscape services (Green Industry Research Consortium, 2013).
There are more than 20,000 commercial rose cultivars, most of which are complex tetraploid or triploid hybrids derived from eight to ten wild diploid and a few tetraploid rose species. Rose breeding has harnessed the specific ability to produce cultivars with the desired combinations of color, form, fragrance, and hardiness.
The greatest danger for cultivated roses in the world is disease and insect infestations. Commercial roses are generally grown with pesticides to decrease the incidence of pathogens. This, however, is at substantial expense to the grower and the environment. As a result, the incorporation of particular disease resistance, especially to blackspot fungus(Diplocarpon rosae [Lib.] Wolf), powdery mildew (Sphaerotheca pannosa [Wallr. ex Fr.] Lev), rust (Phragmidium spp.), Cercospora leaf spot Rosisphaerella rosicola (teleomorph: Mycosphaerella rosicola, syn: Passalora rosicola, Cercospora rosicola Pass. and Pseudocercospora puderi), and rose rosette disease caused by the rose rosette virus, into rose genotypes is greatly desired.
For the last 200 years, rose breeders have made tremendous advances in the development of better rose flower types and plant growth types. A rainbow of colors and a wide spectrum of flower and plant forms are available today. While we owe much to those who created this cornucopia of beauty, extensive research remains to be done. Little sustained effort has been devoted to developing plants with resistance to disease and pests.
The Rose Breeding and Genetics Program is a multidisciplinary team that combines the traditional sciences of breeding, genetics, plant pathology, entomology, and plant physiology with the newly developing tools of biotechnology. The main objective is to develop disease resistant garden rose cultivars for the rose community.
To learn more about the trends of rose production in the United States, please refer to A Recent History of Changing Trends in USA Garden Rose Plant Sales, Types, and Production Methods and the associated presentation by H.B. Pemberton and J.F. Karlik.