Detached shoot treatments cannot replace whole-tree assays when phenotyping for apple resistance to Neonectria ditissima

  • Reiny W.A. Scheper
  • Brent M. Fisher Plant & Food Research
  • Tara Taylor Plant & Food Research
  • Duncan I. Hedderley Plant & Food Research
Keywords: European canker, phenotyping, disease resistance, disease incidence, hydroponic conditions, potted trees, detached shoots

Abstract

To develop a fast phenotyping method for European canker resistance of apple, detached-shoot assays were compared with whole-tree phenotyping methods. Disease incidence and lesion length in detached shoots and potted trees of six apple accessions were compared after inoculation with Neonectria ditissima conidia in a glasshouse. Detached shoots were placed in aerated water or in a Chrysal solution, with and without water changes. ‘Royal Gala’ trees had the highest disease incidence (90%) and ‘Robusta 5’ trees remained lesion-free. The treatment-accession interaction effect was significant, with higher disease incidence in detached shoots of ‘Robusta 5’ (4—32%) than ‘Braeburn’ (0—2%), while ‘Braeburn’ trees had a high disease incidence (64%). ‘Robusta 5’ had smaller lesions than the other accessions, but significant differences between accessions were observed on only one of three assessment dates. None of the detached-shoot assays resulted in a similar ranking of the accessions compared with the potted-tree assay, using disease incidence or lesion length. Detached-shoot treatments cannot replace whole-tree assays when phenotyping for European canker resistance of apple.

Published
2018-07-28
How to Cite
Scheper, R., Fisher, B., Taylor, T., & Hedderley, D. (2018). Detached shoot treatments cannot replace whole-tree assays when phenotyping for apple resistance to Neonectria ditissima. New Zealand Plant Protection, 71, 151-157. https://doi.org/10.30843/nzpp.2018.71.137
Section
Vol 71 Apple Pathogens 2018

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