Pathogenicity and Vegetative Compatibility of Fusarium oxysporum f. sp. phaseoli in Greece

Twenty-seven isolates of Fusarium oxysporum (Fo) obtained from diseased beans from Greece were characterized for pathogenicity to bean cultivars and vegetative compatibility (VCG). Twenty-three isolates were intermediate to highly virulent to five local bean cultivars and characterized as F. oxysporum f. sp. phaseoli (Fop). Zarganes, Gigantes (two selections) and Chondra were the most susceptible cultivars, while Psila was resistant to 10 of the isolates. Four Fo isolates were not pathogenic against tested cultivars. By demonstrating complementation assay, with nitrate non-utilizing (nit) mutants, 15 pathogenic isolates were grouped into one VCG, two isolates into a previously identified VCG 0165 and six into unique unclassified VCGs. The four non-pathogenic Fo isolates failed to anastomose with any tested pathogenic Fop strain. Our results suggest that most of Fop isolates in Greece belong to one VCG.