title: Semienclosed Tube Cultures of Bean Plants (Phaseolus vulgaris L.) for Enumeration of Rhizobium phaseoli by the Most-Probable-Number Technique.
abstract: The semienclosed tube culture technique of Gibson was modified to permit growth of common bean (Phaseolus vulgaris L.) roots in humid air, enabling enumeration of the homologous (nodule forming) symbiont, Rhizobium phaseoli, by the most-probable-number plant infection method. A bean genotype with improved nodulation characteristics was used as the plant host. This method of enumeration was accurate when tubes were scored 3 weeks after inoculation with several R. phaseoli strains diluted from aqueous suspensions, peat-based inoculants, or soil. A comparison of population sizes obtained by most-probable-number tube cultures and plate counts indicated that 1 to 3 viable cells of R. phaseoli were a sufficient inoculant to induce nodule formation.
authors.affiliation: Empresa Brasileira de Pesquisa Agropecuaria, Centro Nacional de Pesquisa de Arroz e Feijão, Caixa Postal 179-74000 Goiânia, Goiás, Brazil; Department of Microbiology and Public Health, Michigan State University, East Lansing, Michigan 48824; and Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706.
authors.forename: R S
authors.initials: RS
authors.lastname: Araujo
authors.forename: J
authors.initials: J
authors.lastname: Maya-Flores
authors.forename: D
authors.initials: D
authors.lastname: Barnes-McConnell
authors.forename: C
authors.initials: C
authors.lastname: Yokoyama
authors.forename: F B
authors.initials: FB
authors.lastname: Dazzo
authors.forename: F A
authors.initials: FA
authors.lastname: Bliss