Assessing Cultivated Strawberries and the FragariaSupercore for Resistance to Soilborne Pathogens

Abstract

The soilborne pathogens Verticillium dahliae, Macrophomina phaseolina, and Fusarium oxysporumf. sp. fragariae are a challenge for strawberry ( Fragaria× ananassa) growers. The loss of methyl bromide and increasing restrictions on the use of other fumigants due to health and environmental concerns make the development of effective non-fumigant disease control options critical for the future economic survival of the industry. Genetic resistance can be an economical option to manage these diseases. Little is known about the genetics mediating resistance to these pathogens. Thus, there is a great need to identify sources of resistance for these pathogens to assist future breeding efforts. As such, 21 F.× ananassaaccessions and 30 individuals from the FragariaSupercore were evaluated for V. dahliae, M. phaseolina, and F. oxysporumf. sp. fragariaeresistance. Six plants of each accession were inoculated via root dips prior to planting and percent mortality was recorded. Accessions with less than 33.3% mortality were considered resistant. Of the accessions evaluated, 29 were resistant to V. dahliae, 20 were resistant to M. phaseolina, and 36 were resistant to F. oxysporumf. sp. fragariae. Future work is needed to identify the resistance genes, develop tools for DNA-informed breeding, and introgress resistance from the Supercore into F.× ananassa.