Effects of <i>Rhizobium japonicum</i> Strains on Soybean Yields¹

Abstract

Soybean varieties ( Glycine max (L.) Merrill) were inoculated with 28 strains and two commercial preparations of Rhizobium japonicum . The effect of each strain on the yield of five varieties was evaluated and significant yield differences were found associated with certain strains. Four different environments were studied and in three of the environments, which were free of R. japonicum , a significant strain ✕ year interaction was observed. No significant strain ✕ variety interactions were indicated. Only 5 to 10% of the nodules on plants grown in a field with an established R. japonicum population were derived from the inoculum introduced into the soil on the seed.