Numerical Analysis of Phenotypic Features of Pseudomonas solanacearum Strains Isolated from Tobacco and Other Hosts in South Africa. Marthie C. Engelbrecht, Department of Plant Pathology, University of Stellenbosch, Stellenbosch 7600, South Africa. M. J. Hattingh, Department of Plant Pathology, University of Stellenbosch, Stellenbosch 7600, South Africa. Plant Dis. 73:893-898. Accepted for publication 5 June 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0893.

Forty-six strains of Pseudomonas solanacearum from South Africa and 13 reference strains were subjected to numerical phenetic analysis using 55 unit characters. Data were analyzed by applying unweighted pair-grouping clustering on the simple matching (S_sm) coefficient. At 85% S_sm, three phenons and two solitary strains were distinguished. Phenons 1, 2, and 3 corresponded, respectively, with biovars III, I, and II. All strains in phenons 1 and 2 were assigned to race 1 and those of phenon 3 to race 3. At 95% S_sm, three groups were recognized within each phenon. None of the reference strains corresponded with South African strains in all of the features examined. Apart from five potato strains of group 3A, all South African strains of P. solanacearum were assigned to groups 1A and 1B of phenon 1. Local race 1 tobacco strains were highly virulent on other host species tested.

Keyword(s): bacterial wilt.