Dr. Campbell G. Davidson Manager
Morden Research Centre Unit 100-101 Route 100 Morden, MB
Research on the breeding and development of new roses continues at Morden. Due to changes in our funding, the research is proceeding at a somewhat lower level of intensity. With the Federal budget of 1994 there was a wide range of budget adjustments made throughout the whole Federal service. Our rose and herbaceous perennial breeder position, occupied by Lynn Collicutt, was one of the positions deleted from our budget. This means that we are no longer able to devote as many of our resources to breeding these crops.
In realigning the programs in the Landscape plant unit, we have been able to keep some of the breeding activities going, as well as starting a number of new projects. These new projects are being established using funds from our Matching Investment Initiative (MII) to hire a summer student assistant. With this program we can match contributions from industry or other interested parties, thereby potentially doubling the actual industry contribution. In this case, funding has been obtained from the Canadian Ornamental Plant Foundation (COPF) and the Canadian Red Cross Society.
Two of the new projects relate to the common disease on roses: blackspot (Diplocarpon rosae). For many of you who have grown our introductions, you will know that blackspot can cause significant problems. A regular fungicide program may be required to control the pathogen, depending on your growing site. Over the past winter, with the very capable help of Dr. Allen Xue, one of our pathologists at the Centre, we have cultured the fungus in the lab. Dr. Xue has developed inoculation techniques to infect plants with the disease under greenhouse conditions. Once the pathologists were confident that we could get reasonable fungal activity (these thing often don't cooperate in controlled conditions) we started the comparative study. In this study, completed this past winter, we examined 11 cultivars or selections from our programs and rated the disease incidence, numbers of lesions per leaf, lesion size and sporulation of the fungus using three different isolates of the disease. We obtained two of the isolates from our fields at Morden and the third from the Ottawa rose collection. From these trials we were able to identify five lines that were very susceptible (readily get the disease), two that were moderately susceptible, three slightly susceptible and one resistant type. The resistant one, for obvious reasons, is most interesting. This plant is also yellow flowered which makes it even more valuable! Interestingly, the yellow selection that was resistant in the greenhouse test was rated poorly for resistance in the field. Discrepancies between the greenhouse and field studies are not uncommon. These are often indicative of the complex reactions that take place in nature and underline the need for more research.
We are continuing the project this summer with field trials. We will be planting all the same lines in a plot and monitoring the disease reaction in both inoculated material (like the winter greenhouse study) and naturally inoculated material. This should help to clarify the disease situation much more. Hopefully, by the end of the summer we will have a better handle on blackspot disease and be able to use this information to develop better screening studies.
The second new trial we are establishing also deals with blackspot. Several years ago, I visited in Russia and Sweden and visited with a rose breeder at the Swedish Agricultural University near Lund (southern Sweden). Their program has similar objectives to ours, in that they are trying to replace the traditional "Hybrid Tea" type roses which are generally not hardy, with locally developed and grown cultivars. blackspot disease is also an important problem.
The Swedish plant breeder, Ulrika Carlson, has since decided to initiate her PhD. studies. Her thesis topic is blackspot disease on roses. I have been asked to assist in her program by being an external advisor. As a result, this spring we have set up duplicate trials in Morden, Manitoba, Canada and Lund, Sweden. We have over 100 species, cultivars or selections (from Germany and Sweden) planted. Over the next two years we will be monitoring disease incidence as well as hardiness and adaptability to the two very different growing conditions (eg. hot and dry summers with very cold winters vs cool and moist summers with a more moderate winter). This should provide a tremendous amount of information concerning the disease as well as the other characteristics. If our plans move in the direction we hope, the next phase of the study will involve molecular markers. These markers will "tag" the DNA so we can identify specific plants with the attribute that we have identified as valuable (eg. resistant or susceptible to blackspot disease). In an "ideal" world, we would then be able to screen all of our seedlings before they are a month old to determine if they have the necessary genetic material to warrant further evaluation in the field. This would enable us to greatly reduce the numbers of plants we place outside, which should ease the evaluation part of the program and consequently reduce our costs and increase our efficiency. "In an ideal world" are the key words; but this is what research is all about. A third project is just nicely in the planning stages at the present. I have been working with a number of rose breeders in the USA regarding plant exploration. We are in the middle of developing an agenda for a plant collection trip to China. China, as you may know, is home to a great many species of roses. In fact, China is an important "Centre of Diversity" for the genus Rosa, with about 93 of its 200 species and about 150 varieties present. Many rose species in the wild state (in their natural habitat) are threatened by population encroachment. Characters found in various Chinese roses include disease resistance (blackspot, powdery mildew, rust), cold hardiness, ever blooming, white or yellow petal colour, intense scent, and double flowers.
There are few rose varieties that have high levels of disease resistance and cold hardiness plus other desirable horticultural traits. The incorporation of cold hardiness and resistance to the blackspot fungus (Diplocarpon rosae), powdery mildew (Sphaerotheca pannosa, rust (Phragmidium spp.) and rose mosaic virus (PNRSV), into rose genotypes would make this crop even more adaptable for general landscape use and reduce the number of chemicals used in their production and in their culture. Some preliminary research has indicated that high levels of these traits exist in the Chinese species.
A substantial part of the diversity in the commercial rose germplasm of today resulted from the introduction of a few Chinese roses into Europe around the year 1800. Modern cultivated roses are believed to be founded on 8 to 10 wild diploid species, leaving 95% of the genus untapped from a plant breeding point of view. The introduction of such species into modern rose breeding programs would be highly beneficial. The objective of the first trip is to visit the major rose collections in China, collect (or identify material to be collected) some wild material, establish contact and meet with our counterparts to organize future studies (eg. subsequent trips), and finally to establish the making of a repository for rose germplasm (to be established in Nanjing). All collections (cuttings, budwood, and/or seed) will be established in the Chinese repository and as material is available, it will be sent to the USA via a USDA Plant Germplasm Inspection Station. As appropriate material will be incorporated into the National Plant Germplasm System, curated at the USDA National Arboretum. As much as possible, collections will be documented with voucher herbarium specimens and complete passport data. Subsequent trips would focus more on collecting wild germplasm with our Chinese counterparts. It is a long-term project but I, as well as the other members of the team think that it is a real opportunity that should be "explored" to the fullest. Although the Americans will be maintaining the germplasm in the USA, we (Canadians) will have access to it through our participation in the project as well as germplasm exchange agreements in place already. It will be a very expensive project; the airfare alone is over $2000. As we get closer to the projected departure dates (tentatively set for 1997), I will be soliciting financial assistance from various groups across Canada. The Canadian Rose Society will undoubtedly be one of these!
Our regular breeding program continues to make progress. This year we introduced a new rose: 'Hope for Humanity'. This cultivar was introduced in conjunction with the Canadian Red Cross Society in honour of their 100th anniversary. 'Hope for Humanity' is a "blood" red rose with good repeat flowering. Plants are only available from the Red Cross (contact Stefany at 204-982-8367, 500-240 Graham Ave. ,Wpg, MB, R3C 0J7) until 1998. The Red Cross is using this as a fund raising project as well as one of their Centennial projects. This would be a good project for the Canadian Rose Society to get behind! After 1998, the plant will be available from regular commercial sources. We are also in the final stages of selecting a white flowered "Parkland" type rose. If our advanced trials proceed as we anticipate, this will be the next new cultivar from Morden.
This spring we saw over 5000 new seedlings planted. These are our lifeline for new cultivars. These will be selected, rogued and evaluated for the next three years. Let's hope for more new and interesting plants! The seedlings were raised from controlled crosses we completed last season. Our targets for crossing include white, yellow and dark red flowers and of course, disease resistance, hardiness and repeat blooming. This past winter and spring, we had a large number of new crosses made in the greenhouse as well as getting in new germplasm for the breeding program. We hope to be able to maintain the momentum we have established at Morden and develop new roses that are well adapted to our northern climate as well as being valuable from a horticultural sense. Breeding roses is an exciting business and one that we hope to be able to continue for some time.
Interesting Rose facts: Roses are among the world's most important ornamental crops. In North America alone, garden roses account for $350,000,000 in annual sales to 25,000,000 households. In 1990, about 63,000,000 rose plants were produced in the North America. The market for rose cut flowers alone in the USA (1991) is worth $200,000,000.