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Report, 2012

Genetic basis for resistance against fruit tree canker in apple

Ghasemkhani, Marjan

Abstract

Neonectria ditissima (formerly Neonectria galligena, anamorph Cylindrocarpon heteronema) is the causal agent of fruit tree canker which is regarded as a serious economic problem in horticulture. This fungus causes notable damage to apple trees and it is very important in some regions, especially North western Europe, where it can result in death of spur shoots and branches. Although it occurs in a wide range of temperatures, it is associated with wet weather and climate has an important effect on the geographic distribution. The fungus produces conidia and ascospores, both of which are dispersed and cause infection during prolonged periods of rainy weather. Also, spores produced on the infected wood can act as an infection source in the orchards. The fungus can therefore be introduced into new orchards with infected planting material from other orchards or tree nurseries. Chemical and mechanical control like spraying of fungicides, covering wounds with paint, and cutting out infected branches, do not prevent the occurrence of epidemics. Breeding cultivars with a high level of resistance towards canker would be of great help towards the avoidance of this disease. Apple cultivars show variable levels of partial resistance to the fungus, whereas complete resistance has not yet been reported and no major genes have been identified. Therefore, apple genotypes with comparatively high levels of genetically determined partial resistance should be identified for use in apple breeding.

Keywords

Apple canker; Neonectria ditissima; Neonectria galligena; Nectria galligena; Fruit tree canker

Published in

Introductory Paper at the Faculty of Landscape Planning, Horticulture and Agricultural Science
2012, number: 2012:7, pages:
Publisher: Faculty of Landscape Planning, Horticulture and Agricultural Science, Swedish University of Agricultural Sciences

Authors' information

Ghasemkhani, Marjan
Swedish University of Agricultural Sciences, Plant breeding and Biotechnology

UKÄ Subject classification

Plant Biotechnology
Genetics and Breeding
Agricultural Science

URI (permanent link to this page)

https://res.slu.se/id/publ/78907