Screening wild cherry (Prunus avium) for resistance to bacterial canker by laboratory and field tests
Currently, bacterial canker caused by Pseudomonas syringae is a major cause of dieback and tree death in wild cherry (Prunus avium) plantations. The evaluation of breeding collections is needed to produce less susceptible clones or cultivars. Resistance tests were performed using excised shoots (1 and 2 years old) from 79 clones in the laboratory. A subset of 10 clones was also tested in the field. The clones were inoculated with four to seven isolates of a set of 15 isolates of P. s. pv. morsprunorum, P. s. pv. syringae, P. s. pv. persicae, P. syringae pv. avii and P. fluorescens. In the laboratory tests, older and larger shoots were more susceptible. In the field test, size and age of the shoots were not related to girdling by the bacterial canker. Two-year-old shoots were best for clonal discrimination. Correlations between 1 and 2-year-old shoots were significant but not high. The isolates varied a lot between experiments, but as the clone × isolate interactions were always low, breeding could thus be facilitated. The ranking of clones was conserved quite well between two laboratory tests, but not between two others. Good agreement was found for the best clones in the laboratory tests and in the field test. However, the two worst clones in the latter were among the best in one laboratory test. At least two independent tests in the laboratory are needed to evaluate resistance/susceptibility of clones. Broad sense heritability for resistance varied from 0.27 to 0.51. Although moderate, such heritability clearly encourages a breeding approach to reduce the problem of bacterial canker.
Document Type: Research Article
Affiliations: 1: INRA Orléans, Unité amélioration, génétique et physiologie forestières, Olivet Cédex, France., Email: email@example.com 2: HRI, East Malling, West Malling, Kent, ME19 6BJ, UK 3: UMR INRA-Université d'Angers-INH, Pathologie végétale: biodiversité, écologie, interactions bioagresseurs/plantes, Beaucouzé Cedex, France
Publication date: 2004-12-01