Susceptibility of Cider Apple Accessions to European Canker—Comparison between Evaluations in Field Planted Trees and Rapid Screening Tests

European canker, caused by <i>Neonectria ditissima</i> Bres., is an economically damaging fungal disease of apple. Breeding new cultivars with a high level of resistance to European canker is the main aim of apple breeding programs. Observations of symptoms in naturally infected trees we...

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Bibliographic Details
Main Authors: Álvaro Delgado, Belén García-Fernández, Antonio Gómez-Cortecero, Enrique Dapena
Format: Article
Language:English
Published: MDPI AG 2022-04-01
Series:Plants
Subjects:
Online Access:https://www.mdpi.com/2223-7747/11/9/1145
Description
Summary:European canker, caused by <i>Neonectria ditissima</i> Bres., is an economically damaging fungal disease of apple. Breeding new cultivars with a high level of resistance to European canker is the main aim of apple breeding programs. Observations of symptoms in naturally infected trees were carried out in 400 apple accessions in Asturias (north-western Spain). Young and mature field planted trees were assessed under conditions highly conducive for <i>N. ditissima</i> development. The results demonstrated that juvenile trees (4-year-old) barely showed noticeable symptoms whereas a wide variability in the levels of resistance among accession was observed in mature trees (14-year-old). Around 28% of the locally maintained collection resulted to be highly resistant to this disease in the region. Field observations on mature trees were also compared to four rapid screening tests based on artificially induced lesions. Spearman correlation analysis using two resistance parameters revealed that none of the methods resulted in similar rankings of cultivar susceptibility as some accessions that were ranked as resistant for a given test turned out to be susceptible in the field. This study might suggest that whilst conventional resistance phenotyping techniques are time-consuming, the outcomes of this approach still seem the preferred option to assess the response to <i>N. ditissima</i> of apple accessions.
ISSN:2223-7747