Resistance sources to Xanthomonas fragariae in non-octoploid strawberry species

Forty-three accessions from 11 strawberry species were screened in the greenhouse for resistance to three strains of Xanthomonas fragariae Kennedy and King. Among the accessions tested, Pen-5 of Fragaria pentaphylla Losink expressed either no symptoms or a hypersensitive reaction, while accessions Pen-2 and Pen-4 developed either no symptoms or restricted water-soaked lesions. Two accessions of E moschata Duch were characterized by reduced translucency at the inoculation site in the course of symptom development. These accessions, representing three resistance types, were classified as highly resistant, resistant, and moderately resistant, respectively, based on mean separation of disease severity ratings. The classifications proved to be consistent with the results from measurements of bacterial populations on inoculated leaves of those genotypes. The study suggests that species of E pentaphylla and E moschata harbour diversified sources of resistance. Resistant genotypes were not detected in E nilgerrensis Schlect, E daltoniana J. Gay, E nubicola Lindl, E gracilis Losinsk, E iinumae Makino, E vesca L., E viridis Duch, or E orientalis Losinsk.