The compatibility of the strains in the mixtures was determined on TSA plates. Bacterial strains were streaked at a 90-degree angle from each other. The plates were incubated at 28 °C for 48 h and observed for presence or absence of an inhibition zone. Absence of inhibition zone indicated compatibility of the tested strains, and the presence of inhibition zones indicated incompatibility. The methods were the same as previously described. The mixture of PGPR strains were prepared by combining equal proportions of each strain prior to application to the seed. The experiment was conducted twice