CCBAU30138 was the most effective Rhizobium strains in nitrogen fixation screening for Vector cultivar in greenhouse. Study on competitive nodulation ability of CCBAU30138 strain in field test by using RAPD Molecular Marker Method. The results showed that: DNA extracted from nodules and strains by freeze- thaw bacterial cell lysates could be amplified as template for PCR, the same as the total DNA from strain and root nodules. RAPD-PCR amplification of Rhizobium meliloti DNA obtained from nodules isolates t...