[Numerical taxonomy of several pathovars of Xanthomonas campestris]

Numerical methods were used in order to study the relationships between 26 bacterial strains of 18 pathovars of Xanthomonas campestris according to 115 morphological, cultural, physiological and pathogenic characteristics. Similarity for each pair of cultures was calculated by simple matching coefficient. Using single linkage method of association, the strains fall into a major group formed by pathovars undulosa, translucens, secalis, hordei, pelargonii, hederae, pruni, cucurbitae, zinniae, citri, holcicola, vesicatoria, juglandis, campestris and begoniae, clustered at a similarity level of 76.5%. Xanthomonas campestris pv. gummisudans, X. campestris pv. papavericola and X. campestris pv. ricini appeared in separate branches at similarity levels of 74, 66, and 62%, respectively. The results demonstrated that Xanthomonas campestris pathovars formed a close group with high similarity of morphological and physiological characteristics, being only distinguished by their host range. In cross-inoculations, the strains showed many relationships but this "pathogenicity" may not of itself constitute a differential character.