Isolation and evaluation of phosphate solubilizing rhizobia from root nodules of faba bean (Vicia faba L.) in Morocco

A study was conducted to evaluate the phosphate solubilization ability of rhizobial isolates and their effect on symbiotic effectiveness of faba bean (vicia faba l.). to achieve this aim,30 isolates were sampled from root nodules of faba bean in different geographical regions in morocco. these isolates were evaluated with two reference strains (psra and psrb) of rhizobium leguminosarum for their resistance to environmental constrains such as ph,salinity and temperature variation. in addition,phosphate solubilization was performed on sperber's basal mediums with different amounts of glucose (m1,m2 and m3). besides,an experimental design was carried out under greenhouse conditions in order to evaluate the effect of phosphate solubilizing rhizobia (psr) on symbiotic effectiveness parameters of faba bean. the results showed that among all tested psr ; psr19,psr26,and psr29 were more resistant to extreme stresses and have shown a significant rate of solubilization on sperber's basal mediums (p < 0.05). all psr have a significant effect on symbiotic effectiveness parameters (p < 0.01). psr29 showed the highest number of nodules (34.333 ± 1.527. plant-1),of nodule dry weight (53.077± 3.434 mg.plant-1),shoot dry weight (1.039± 0.051 g.plant-1) and was highly effective (se=81.35%). overall,psr19,psr26 and psr29 were found to be the most performant and may be recommended as biofertilizers in defected soils to decline the use of chemical fertilizers.