Cross-pathogenicity between Formae Speciales of Fusarium oxysporum, the Pathogens of Cucumber and Melon |
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Authors: | D Cafri J Katan and T Katan |
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Institution: | Authors' addresses: Department of Plant Pathology and Microbiology, Faculty of Agricultural Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100;;Department of Plant Pathology, ARO, The Volcani Center, Bet Dagan 50250, Israel (correspondence to J. Katan. E-mail: ) |
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Abstract: | The population structure of Fusarium oxysporum f. sp. cucumerinum was studied using the vegetative compatibility grouping (VCG) approach. All 37 of the examined isolates from Israel were assigned to VCG 0180, the major VCG found in North America and the Mediterranean region. Approximately two‐thirds of the tested isolates were pathogenic to both cucumber and melon, but cumulatively they were more aggressive on cucumber, their major host, than on melon. Disease symptoms on melon plants were less destructive and often expressed as growth retardation. Melon cultivars differing in Fom genes for resistance to F. oxysporum f. sp. melonis were inoculated with three isolates of F. oxysporum f. sp. cucumerinum. Results showed that Fom genes do not confer resistance to F. oxysporum f. sp. cucumerinum, although different horticultural types may respond differently to this pathogen. The reciprocal inoculation of F. oxysporum f. sp. melonis on cucumber, using four physiological races, did not result in disease symptoms or growth retardation. It is concluded that cucumerinum and melonis should remain two distinct formae speciales. |
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Keywords: | Cucumis Fusarium wilt vegetative compatibility group |
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