Abstract

Roses are the most common flowering plants in Italian gardens, since ancient times to the present day. In Italy there are at least 24 native species, distributed throughout the territory, with R. canina as the most widespread species, with its countless forms findable in hedgerows, woodland edges and on scrubland, followed by R. agrestis on sub-acidic soils. For gardening and landscaping, the use of HT hybrids common in the years 1950-60, has been progressively reduced in the last decades by the reintroduction of old roses with more luxuriant and versatile plant shapes, higher resistance to diseases and environmental conditions, lower maintenance and so much history behind. Several public gardens and above all private rose collections have been established and many nurseries have arisen as a result, specialized in the sale of roses, especially old ones. The SOI (Italian Society for Horticultural Science) counted 2 certified rose collections but their number is much higher and includes other rose gardens such as The Botanical Rose Garden of Gianfranco and Carla Fineschi (Cavriglia, FI), The Museum of Ancient Roses (Montagnana MO), The Garden of Rose (Ronzone, TN), The Rose Garden Vacunae Rosae (Roccantica, RT) and The Rose Garden of the Municipality of Rome hosting the International Rose Competition from 1933, now at its 82^nd edition. It should also be remembered The Monza Rose Garden, which hosted 51 editions of the International New Rose Competition and in 2004 received the Award of Garden Excellence by the WFRS. Finally, the experimental and didactic Rose Garden ‘Raffaele Bazzocchi’ in Faenza (RA) was established in the 1990s and from 2020 hosts The UNIBO International New Rose Trials, specifically aimed at identifying disease-resistant new hybrids, suitable for low-maintenance and gardening in the increasingly hot and dry Mediterranean environment.

Biography

Dr. Maria Eva Giorgioni is associate professor at the Department of Agricultural and Food Sciences of the University of Bologna where she carries out research and teaching on ornamental plant production, planning plant growth under greenhouse, artificial lighting, nursery production, design and maintenance of green spaces, parks and gardens. Since the 1990s she has been interested in old and modern landscape roses, evaluating their adaptability to low maintenance. She currently is the convener and the scientific referent of The UNIBO International New Rose Trials, today at the 5th edition, under the auspices of the World Federation of Rose Societies.

Abstract

The disease triangle shows that three fundamental elements are required to co-exist for a plant to become infected with disease. These are the presence of the pathogen capable of causing disease, a susceptible host plant and favourable environmental conditions. If any of these is not present, then no disease occurs. 

Species and cultivars of the genus Rosa are susceptible to a range of fungal, viral and bacterial diseases. These diseases cause a range of symptoms on rose plants including necrosis or death of plant tissue, stunting of growth or overgrowth of plant tissue.

Garden roses have long been perceived by the general gardening public as being susceptible to diseases. There has also been a perception that applications of agrichemicals are required to be able to successfully grow roses.

In order to enhance their appeal to a wider public audience, roses need to have high tolerance to disease. Many rose breeders, both professional and amateur from around the world, have for many years actively selected new introductions from no spray selection programs.  

Growing disease tolerant roses also requires good cultural practises such as location, plant spacing, pruning, nutrition and irrigation as well as choice of cultivar. These all contribute to the health of roses grown in gardens.

This lecture will look at what breeding work has been done to improve disease tolerance and look at possible avenues for future work. This will focus on the four common diseases Blackspot (Diplocarpon rosae), Rust (Phragmidium tuberculatum), Powdery Mildew (Podosphaera pannosa) and Downy Mildew (Peronospora sparsa) which cause the most problems for rose growers. It will also look at how rose culture can affect disease tolerance and suggest methods that can be utilised. 

Biography

Mr. Hayden Foulds is the current President of the New Zealand Rose Society, also serving as Editor of its publications. He is also heavily involved with the International Rose Trials in Palmerston North and has just started to breed roses.  Hayden has written numerous articles for publications in New Zealand and abroad.

Hayden has a Batchelor of Applied Science (Horticulture) from Massey University and is employed as a Propagation Manager for a New Zealand Native Plant Nursery near Palmerston North. He is also President of the International Plant Propagators Society (IPPS) New Zealand region.

Abstract

Disease resistance in plants is defined as the ability to resist attempts by pathogens to attack and parasitise plant tissues. Disease resistance strategies are extremely diverse and vary between species and specific plant-pathogen interactions. This is due to the large number of defence mechanisms that plants use to develop resistance, ranging from structural barriers to induced biochemical processes. Genetically determined forms of resistance vary from quantitative to oligogenic to monogenic, with quantitative resistance factors generally being more durable than monogenic forms.

Roses are attacked by a wide range of pathogens and pests and do not differ in their basic forms of resistance from other plant species, some of which are much better studied. Over the past few decades, numerous analyses of resistance to the most important pathogens of garden roses have revealed a number of interesting sources of disease resistance, some of which have already been used in commercial rose breeding. A few examples for these sources will be presented here. However, scientific approaches to disease resistance breeding have not been widely adopted in commercial rose breeding. However, national programmes such as the German ADR trials or the Earth-Kindä rose trials in the USA are suitable tools for selecting tolerant rose varieties and are also briefly described here.

Biography

Dr. Thomas Debener studied biology at the Universities of Bochum, Marburg and Cologne in Germany. He obtained his PhD in 1986 on molecular markers in potatoes, worked as a postdoctoral researcher from 1990 to 1992 on disease resistance in Arabidopsis, and in 1993 started his own research group at the Institute of Ornamental Plant Breeding, working on genetic analyses in roses and other ornamental plants. In 2004, he was appointed Professor of Molecular Plant Breeding at Leibniz University Hannover. His research focuses on genomics and disease resistance in roses, potatoes and other crops.

Abstract

Rose Rosette Disease is caused by the rose rosette emaravirus that is transmitted by a minute eriophyid mite. This disease is native to North American and in the early 1990s began to cause significant death among garden roses in the landscape. By the 2010s, garden roses were dying by the thousands and large landscape companies began to not plant roses in their projects. In 2013, the rose industry in the USA convened a Rose Rosette Disease Conference that brought together all the stakeholders to better define the problem and chart out a plan to resolve it. This resulted in national program which initiated a focused research program in 2014 and has continued until the present. This initial research developed the diagnostics for the RRV, basic knowledge about the biology of both the rose rosette emaravirus and the vector mite (Phyllocoptes fructiphilus), management approaches to control RRD, evaluated 100s of roses for their resistance to RRD, created genetic populations to identify the genetic basis of resistance, developed molecular tools to accelerate the breeding of RRD resistant roses, and established a web site (roserosette.org) with maps of the distribution of and the best information available for the identification and management of RRD. Although, there are management strategies that can lower the virus pressure and mite populations in the field, the most desirable approach due to its ease of use is RRD-resistant cultivars. Thus, far we have identified two genes which condition partial resistance to this disease. The current research is elucidating the mechanism of the resistance conditioned by these genes as well as developing the genomic tools to accelerate the development of RRD-resistant roses.

Biography

Dr. David Byrne, Professor Emeritus in Horticultural Sciences at Texas A&M University held the Basye Endowed Chair in Rose Genetics. In the early 1990s, working with Dr. Robert Basye, a rose breeder and retired Professor of Mathematics, he began the Rose Breeding and Genetics Program which was enhanced by the donation from the Father of the Miniature Rose, Ralph Moore. He has led national projects to develop rose rosette and black spot resistant roses, develop and integrate computational tools to utilize genomic information in polyploid crop breeding, and establish the National Clean Plant Network for Roses.