background of modern varieties is relative narrow ( Liu and Liu, 2004 ; Matsumoto et al., 1998 ). The roses obtained before the breeding of ‘La France’ in 1867, the first Hybrid Tea rose, are generally called old garden roses ( Cairns, 2003 ). The beauty of
drought stress is exacerbated on plant establishment and survival, and selection of drought-tolerant plants becomes increasingly important for the development of sustainable landscapes. Roses ( Rosa × hybrid L.) are some of the most common garden plants
Overall sales of garden roses have been declining over the past 20 years in the United States due, in part, to the lack of widely adapted cultivars to heat, drought, and salt stress in landscape environments ( Byrne et al., 2010 ). Conversely, an
field winterhardiness of garden roses ( Rosa × hybrida ). Experimental design and growing conditions. The plants were propagated from cuttings in early-Winter 2016 using foam strips designed for vegetative propagation of cuttings (Oasis strips
. https://doi.org/10.1103/PhysRev.27.779 . Cai X , Starman T , Niu G , Hall C , Lombardini L . 2012 . Response of selected garden roses to drought stress . HortScience . 47 ( 8 ): 1050 – 1055 . https://doi.org/10.21273/hortsci.47
and leaves ( Niu et al., 2008 ). Garden rose ( Rosa spp.) is one of the most economically important and popular ornamental plants in the world. Rose has been traditionally categorized as a salt-sensitive species with salt injury reported within a
Eleven rose cultivars were field planted and evaluated weekly for disease, defoliation, and overall vigor in order to compare natural resistance to blackspot (Diplocarpon rosae). Alternative treatments were also compared for efficacy in low-maintenance disease control. Treatments included a bimonthly application of chlorothalonil, a bimonthly application of a horticultural oil, an application of chlorothalonil based on rain events, and a no-treatment control. Cultivars showed significant differences in disease severity, defoliation, and overall performance, with old garden rose varieties showing more natural disease resistance than modern susceptible varieties included in the study. Chlorothalonil applied on a 14-day spray schedule did provide a significant decrease in blackspot disease severity when compared to other treatments. A significant incidence of secondary disease including Cercospora rosicola and Botrytis cinerea occurred on old garden rose varieties. No treatment differences were found for these diseases. `Belinda's Dream', `The Fairy', and `Red Mediland' ranked highest in overall performance throughout the season.
To enlarge the palette of environmentally-responsible landscape plants, 117 garden rose cultivars were evaluated under minimal input conditions. Other than mulching and irrigation, no other inputs were provided, including no fertilization and no pesticide applications. Plants were established in completely randomized blocks with four reps in the spring of 1998 with data collection beginning in 2000 and continued through 2002. Data on overall performance (an index comprised of flower number, percent of plant covered with flowers and plant growth) and relative chlorophyll content were collected the first and third week of each month from April through October. Disease ratings or incidence ratings were collected for Diplocarpon rosae Wolf (black spot), Alternaria sp. (petal blight) and Sphaerotheca pannosa (powdery mildew). Statistical analysis was performed on the mean data for all dates. `Knockout' was the top rose for overall quality with little or no disease observed, high foliage quality, and continuous flowers from spring until late in the fall. `Knockout' also ranked among the top rose cultivars in terms of overall nutrient concentrations (N, P, K, and Fe) in new growth tissue. Most of the hybrid tea roses such as `Peace' and `Double Delight' died in at least three blocks due to disease and a lack of vigor.
(Wageningen, The Netherlands) for providing unpublished microsatellite loci primer sequences, Ben Vosman for the critical review of the manuscript, and Elena Costa for the help in morphological identification of rose accessions. We very much appreciated the
Roses are among the most popular garden ornamentals in temperate and subtropical zones, but they have a reputation of being very difficult to grow ( Manners, 1999 ). Roses have long been an important landscape plant and there is growing interest in