Genetic resistance to novel resistance-breaking strain of pathogenic fusarium wilt in cultivated strawberry

Monday, August 4, 2025

1:00 PM - 1:15 PM HST

Location: Room 311

Presenting Author(s)

CM

Caitlyn T. Morgan-Bailey (she/her/hers)

Graduate Student Researcher
University of California, Davis
Davis, California, United States

Author(s)

MB

Marta Bjornson, University of California, Davis, Department of Plant Sciences

Project Scientist
University of California, Davis
Davis, California, United States
CE

Christine Jade Dilla Ermita, University of California, Davis, Department of Plant Sciences/ USDA-ARS Salinas

United States Department of Agriculture Agricultural Research Service
Davis, California, United States
DP

Dominique D. A. Pincot, University of California, Davis, Department of Plant Sciences

Postdoctoral Researcher
University of California, Davis
Davis, California, United States
RF

Randi A. Famula

Staff Research Associate and Lab Manager
University of California, Davis
Davis, California, United States
MV

Mishi Vachev

Postdoctoral Researcher
University of California, Davis
Davis, California, United States
PH

Peter M. Henry, USDA-ARS Salinas

Research Plant Pathologist
United States Department of Agriculture, Agricultural Research Service
Salinas, California, United States
MF

Mitchell J. Feldmann, University of California, Davis, Department of Plant Sciences

Associate Professor and Director of Strawberry Breeding Program
University of California, Davis
Davis, California, United States

Abstract Text: Fusarium wilt, caused by the soilborne fungal pathogen Fusarium oxysporum f. sp. fragariae (Fof), presents a significant threat to cultivated strawberry (Fragaria × ananassa) production in California. Complete resistance to Fof race 1 (Fof1) through the Fw1 locus was reported by Pincot et al (2018), with additional loci (Fw2-5) being described by Pincot et al (2022). In 2022, Fof race 2 (Fof2) was identified by Dilla-Ermita et al (2023) in Oxnard, CA as a novel strain that overcomes resistance conferred by Fw1. To investigate Fof2 genetic resistance and identify potential donors for breeding, we inoculated a panel consisting of 598 strawberry accessions compromising heirloom cultivars, octoploid wild species, and breeding lines. Roughly 90% of the plants in the panel died due to Fof2 infection, and all living plants exhibited symptoms of the pathogen. Despite high mortality, our results show that there is at least partial genetic resistance to Fof2 within the evaluated panel (H2 = 0.658, h2 = 0.438). To describe the genetic architecture of resistance to Fof2, we conducted a GWAS and identified two significant QTLs for partial resistance on chromosomes 4C and 5B. Progeny from these potential donors are currently being tested for improved resistance to Fof2. The donors of resistance and loci identified in this study will facilitate the rapid development of cultivars with resistance to Fof2 through marker-assisted and/or genomic seedling selection and backcrossing.