VIRULENCE ASSESSMENT OF RHODOCOCCUS FASCIANS STRAINS ON PEA CULTIVARS

Thirty-one strains of Rhodococcus fascians were assayed for virulence on cultivars of Pisum sativum and Lathyrus odoratus. The growth and de velopment of shoot, root and cotyledon tissues of host plants were aff ected by inoculation with virulent strains of ii. fascians. Principal components analysis of the virulence assays which measured shoot and r oot characters of inoculated plants separated the R. fascians strains into four groups which were associated with high virulence, intermedia te virulence, weak virulence and avirulence. The susceptibility of the various host plants to infection by strains of R. fascians differed.