Abstract

European canker is caused by the fungus Neonectria ditissima (Neonectria galligena, formerly Nectria galligena). The disease causes significant losses to apple production in Sweden and many other countries with a temperate wet climate. Application of fungicides and good horticultural practices do not prevent canker damage in nurseries and orchards. Disease outbreaks damage and even completely destroy trees. To date, complete resistance to N. ditissima is not known in apple, but cultivars differ considerably in their level of partial resistance. To be able to conduct breeding for resistance to European canker, reliable plant tests are urgently needed. Differences in resistance to N. ditissima (colonization rate; CR) in apple cultivars were evaluated by wound inoculations with a standardized number of conidia on cut shoots from mature trees placed in a climate chamber and on potted trees in an unheated greenhouse. Infection percentage (Inf%) was assessed by 'natural' inoculations in leaf scars under high infection pressure in the field. All the experiments were carried out over 2 years. Lengths of lesions were measured at regular time intervals on five occasions for shoots and seven occasions for trees. Considerable differences in CR and Inf% were found among the cultivars. The relative levels of resistance obtained are consistent with previous reports for most cultivars. Assessment of CR (area under curve) and Inf% thus proved to be useful tools for evaluation of resistance to European canker. Also, some potentially new sources of resistance were identified.

Keywords

fruit tree canker; Malus x domestica; susceptibility; disease resistance; phenotyping; Nectria galligena

Published in

Acta Horticulturae
2016, Volume: 1127, pages: 75-81
Title: XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): Proceedings of the International Symposium on Plant Breeding in Horticulture
ISBN: 978-94-62611-39-9
Publisher: ISHS

Conference

29th International Horticultural Congress on Horticulture

SLU Authors

• Gustavsson, Larisa

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

• Ghasemkhani, Marjan

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

• Zborowska, Anna

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

• Englund, Jan-Eric

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network
AMR: Fungus


UKÄ Subject classification

Horticulture


Publication identifier

DOI: https://doi.org/10.17660/ActaHortic.2016.1127.14

Permanent link to this page (URI)

https://res.slu.se/id/publ/79476