Identification of rhizobacteria from maize and determination of their plant-growth promoting potential

During the growing season of 1986, the rhizobacteria (including organisms from the ectorhizosphere, the rhizoplane and endorhizosphere) of 20 different maize hybrids sampled from different locations in the Province of Quebec were inventoried by use of seven different selective media. Isolates were characterized by morphological and biochemical tests and identified using the API20E and API20B diagnostic strips.Pseudomonas spp. were the prominent bacteria found in the rhizoplane and in the ectorhizosphere.Bacillus spp. andSerratia spp. were also detected, but in smaller numbers. In the endorhizosphere,Bacillus spp. andPseudomonas spp. were detected in order of importance. Screening for plant growth-promoting rhizobacteria was carried out in three soils with different physical and chemical characteristics. The results depended on the soil used, but two isolates (Serratia liquefaciens andPseudomonas sp.) consistently caused a promotion of plant growth.Contribution no. 350 of the Research Station, Agriculture Canada, Sainte-Foy, Quebec.