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Epistatic modifiers influence the expression of continual flowering in strawberry

Cockerton, Helen Maria, Nellist, Charlotte Florence, Hytönen, Timo, Litthauer, Suzanne, Hopson, Katie, Whitehouse, Adam, Sobczyk, Maria, Harrison, Richard Jonathan (2022) Epistatic modifiers influence the expression of continual flowering in strawberry. Plants People Planet, 5 (1). pp. 70-81. ISSN 2572-2611. (doi:10.1002/ppp3.10300) (KAR id:96181)


Society Impact Statement:

Until the 1970s, the majority of commercial strawberry varieties produced a single bloom of flowers. However, continuously flowering, everbearing strawberries are now routinely cultivated and use is increasing. Indeed, introgression of the everbearing flowering trait can lead to economic benefits for growers through the production of a continual crop from the same plant. Genetically guided improvement has the power to streamline everbearing generation. As such, the genetic markers reported here can help to identify everbearing individuals at an early time point in the breeding process. Furthermore, these markers can help to improve the predictions of progeny segregation ratios.


Previous work within the community led to the identification of a single dominant allele that controls the everbearing trait. However, frequent observations have indicated that crosses do not segregate in a Mendelian fashion, as would be expected for a trait controlled by a single dominant gene. Therefore, it was hypothesised that one or more unidentified epistatic alleles interact with the major gene.

A genome-wide association study (GWAS) was conducted on 587 June bearers and 207 everbearers to assess the genetic components associated with flowering habit. The segregation ratios of parental strawberry lines with known phenotypes were used to validate the identified alleles.

Three loci including the known major FaPFRU locus and two epistatic modifiers were identified. These modifiers function as enhancers of the everbearing trait in individuals containing a single copy of the FaPFRU everbearing allele and appear to be functionally redundant. Principally, heterozygous individuals required the presence of two modifying alleles in order to allow expression of the everbearing trait.

Inclusion of the epistatic alleles improved the prediction of everbearing segregation ratios; beyond that of a single allele model, however, a large proportion of the variation remained unexplained. Future work should identify the additional repressor and enhancer modifiers not identified here. Discovering the genetic components controlling the everbearing trait can enable genetic informed strawberry improvement.

Item Type: Article
DOI/Identification number: 10.1002/ppp3.10300
Additional information: For the purpose of open access, the author(s) has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising.
Uncontrolled keywords: epistasis, everbearing, flowering time, functional redundancy, genome-wide association study (GWAS), marker-assisted breeding
Subjects: Q Science
Q Science > QK Botany
S Agriculture
Divisions: Divisions > Division of Natural Sciences > Biosciences
Funders: Biotechnology and Biological Sciences Research Council (
Innovate UK (
Depositing User: Helen Cockerton
Date Deposited: 12 Aug 2022 09:56 UTC
Last Modified: 20 Nov 2023 15:42 UTC
Resource URI: (The current URI for this page, for reference purposes)

University of Kent Author Information

Cockerton, Helen Maria.

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