[Study of symbiotic, serological and antibiotic resistance characteristics of different Rhizobium cicerii strains]

The symbiotic performance of 24 isolates of Rhizobium Cicerii, collected from different Tunisien soils, were studied in a growth room and compared to the performance of two international strains (Som and 43). The antibiotic and serologic tests showed a large biogenetic diversity among the different isolates. Three serogroups gathering 18 isolates have been identified. Monchar strain (isolat 12) was shown to be resistant to all the six different antibiotic used. The standard strain 43 produced the greatest number of nodules and the best nitrogen yield in association with "Amdoun" roots, whereas the Menzel bouzelfa isolate brought about the best nitrogen yield in association with "Amdoun" and thus was the most efficient. An interesting result, consisted on the existence of a significant correlation (r = 0.67) between streptomycin resistance of the isolates and their capacity of nodule initiation (infectivity).