Virulence Studies and Resistance to Clavibacter michiganensis ssp. michiganensis in Tomato Germplasm

Abstract

Abstract Six strains of bacterial canker ( Clavibacter michiganensis ssp. michiganensis) , isolated from tomato plants from greenhouses or fields near Cleveland, Ohio, were tested for virulence. The most virulent of the strains was used to evaluate 13 cultivars reported to be resistant to bacterial canker. Eleven of the cultivars were resistant at a high inoculum level (8.5 × 10 8 cells per plant) and the other two only at a lower level (8.5 × 10 2 cells per plant). It was demonstrated that it is possible to identify plants with intermediate resistance using a dilute inoculum of a virulent strain of C. michiganensis