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Home HortScience Relationship between Insect Resistance, Apple Quality Determined
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ZURICH, SWITZERLAND - Apple breeders continuously work to enhance fruit quality, plant health, and productivity. A key challenge for breeders of high-quality apples is that many disease-resistant apple cultivars have undesirable fruit traits such as lack of firmness or sweetness. According to the authors of a new study, the undesirable quality traits frequently associated with pest- and disease-resistant cultivars may be related to resource allocation tradeoffs.

Swiss scientists published a report in HortScience that evaluated the association between insect resistance and fruit quality traits in apples. Author Karsten Mody said that the researchers recognized a need to establish new information on resource allocation tradeoffs for apple breeding programs aimed at creating high-quality disease- and pest-resistant apples.

In experiments using 250 progeny apple genotypes, the data revealed a positive correlation between codling moth fruit infestation and fruit firmness. "Our data also revealed a positive correlation between shoot infestation by green apple aphid and fruit number as well as between aphid infestation and sugar content, but found that infestation by apple leaf miner moth, rosy apple aphid, leaf-curling aphid, and apple rust mite was not significantly related to fruit quality traits," Mody said.

The study noted that the relationship of increased insect infestation and fruit characteristics such as firmness or sugar content points to an increased necessity for plant protection measures in apple cultivars producing high-quality fruits. "Our finding that the association between herbivore resistance and fruit quality was not strongly expressed highlights the potential to breed high-quality pest-resistant apple cultivars by marker-assisted selection, similar to fire blight-resistant high-quality apples," explained Mody.

The scientists recommend the use of genetic markers for fruit quality and pest resistance in marker-assisted breeding programs, noting that studies in other genetic backgrounds or under different environmental conditions could help to assess whether resource allocation tradeoffs between plant growth traits and insect resistance are obstacles for successful apple breeding programs.


The complete study and abstract are available on the ASHS HortScience electronic journal web site:

Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at


Original Article:

Association between Herbivore Resistance and Fruit Quality in Apple
Sibylle Stoeckli, Karsten Mody, Silvia Dorn, and Markus Kellerhals
HortScience 46:12–15. [Abstract] [Full Text] [PDF]

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