Evaluation of Rhizobium meliloti strains indigenous to Sonoran Desert soils by plasmid profile and intrinsic antibiotic resistance
In Arizona, alfalfa (Medicago sativa L.) is not normally inoculated and yet yields are high due to biological nitrogen fixation by indigenous strains of Rhizobium meliloti. The objectives of this study were 1.) to determine the dominant R. meliloti strains indigenous to the Southwest, 2.) to evaluate environmental factors influencing the distribution of these dominant strains, and 3.) to assess the effectiveness of those indigenous strains on a locally adapted alfalfa cultivar.
All places surveyed are included in the zone of serpentin. Almost all hills are slided and collapsed and they have no big tree. The reservoir is being filled with a large amount of slided materials. Four places were chosen along the road for the present survey where some special features of the land-slide were respectively observed and resistivities of serpentin could be distinguished from that of the other material. We have had such a conclusion ac that the resistivity method will be useful for the survey of the land-slide in this district.