Dendrogram depicting relatedness among RSα- and RSβ-specific fingerprints of soybean bradyrhizobia from six field sites, Tokachi (T), Nakazawa (NC), Nagakura (NK), Ami (A), Fukuyama (F) and Ishigaki (I). ‘+’, ‘−’ and ‘e’ indicate B. japonicum hup⁺, B. japonicum hup⁻ and B. elkanii, respectively. The bar in each column (labelled ‘Site’) to the right of the dendrogram indicates from which field the fingerprinted strain came.