The present study aimed to evaluate the occurrence of diazotrophic bacterial associated with sorghum plants, to select efficient sorghum cultivars associated with diazotrophic bacterial, as well as to identify isolates efficient on nitrogen fixation (N²) and indole acetic acid (IAA) production. Fourteen forage sorghum cultivars were cropped in jars under two levels of nitrogen fertilization: 0 and 130kg ha-1 of N. The selection of sorghum cultivars was based on the association with diazothophic bacterial and on the efficiency of nitrogen absorption. Semi-solid enrichment medium was used for the isolation of the diazotrophic bacterial. The occurrence of diazotrophics was verified in all cultivars of sorghum evaluated and, the distribution of the isolates was affected by the plant genotype. All the isolates were able to fix N² and to produce IAA in vitro.
nitrogen fixing bacteria; indole acetic acid production
