NODULATION AND NITROGEN-FIXATION BY SALINITY-TOLERANT RHIZOBIA IN SYMBIOSIS WITH TREE LEGUMES

Fifty-seven Rhizobium sp. strains isolated from tree legumes known to grow under saline conditions were screened for their ability to tolerate different levels of salinity ranging from 0 to 12 dS m-1 electrical conductivity. Four Rhizobium sp. strains isolated from Acacia, Dalbergia, Leucaena and Prosopis were found to be highly tolerant to salinity (9-12 dS m-1) .Salinity-tolerant rhizobia showed better survival, nodulation and nitrogen fixation than salinity-sensitive rhizobia under saline conditions. Thus, biological nitrogen fixation can be significantly increased by inoculating tree legumes with salinity-tolerant rhizobia under saline conditions. © 1990.