The crop wild relative Fragaria vesca as source of resistance against strawberry anthracnose.

The genetic diversity of Fragaria species in situ has great potential for breeding resistance in cultivated strawberries against anthracnose disease. In this study, we investigated the host-pathogen interactions of 72 F. vesca genotypes of various German origins to identify new resistance to Colletotrichum, one of the most economically important genera of pathogens in F. × ananassa cultivation. The host-pathogen interactions were monitored by symptomatic scoring after spray-inoculation of F. vesca genotypes with monoconidial Colletotrichum isolates of different species recently determined in German strawberry fields. We observed significant variation in host-pathogen interaction, ranging from host genotypes exhibiting resistance to a single pathogen strain, to those demonstrating broad-spectrum resistance. The most promising F. vesca genotype, NO 04 002, showed resistance to at least six C. nymphaeae strains and tolerance to other pathogen species. However, the monogenetic resistance gene RCA2, known from F. × ananassa, was not detectable in any of the ancestral F. vesca genotypes, suggesting a more basal resistance. Our study demonstrates the potential of a crop wild relative (CWR), namely F. vesca, as genetic resource for resistance to economically relevant strawberry anthracnose. Since this resistance is based on nonspecific defence mechanisms in the host, it contributes to the development of breeding strategies that are less susceptible to resistance erosion, supporting more sustainable strawberry production.