Breeding for disease resistance in ornamentals

A wide variety of plant species are cultivated for ornamental use as cut flowers, pot and garden plants. The variety of species goes hand in hand with an equally large diversity of problems that are caused by plant pathogens during cultivation and after sale. Improved disease resistance is therefore often a high priority on the wish list of ornamental plant breeders. For food crops, huge efforts are made to develop plant pathology research and breeding. Tools such as bioassays for he
screening of parent and offspring plants, biotechnological tools, or other disease
resistance-oriented approaches result in more resistant cultivars. For ornamentals, however, these techniques and resources have found only limited application.
Here we offer an overview of disease resistance breeding in ornamental plants.
The examples given for specific ornamental crops are primarily based on scientific literature. We also include the practical experience and opinion of commercial breeders to provide insight into common and applied breeding practices. Specific plant-pathogen cases are presented, including Xanthomonas axonopodis pv. dieffenbachiae in Anthurium andreanum, Phytophthora plurivora and Calonectria pauciramosa in azalea (Rhododendron simsii), Calonectria pseudonaviculata and C. henricotiae in Buxus, Fusarium oxysporum f.sp. dianthi in Dianthus caryophyllus, Puccinia horiana in Chrysanthemum x morifolium, and Fusarium oxysporum f.sp. lilii in lily (Lilium).