Out of 210 rhizobacteria isolates 148 were randomly selected and evaluated for growth promotion of rice plants, under greenhouse conditions.
An experiment was conducted for mass screening of isolates with cultivar Primavera using a completely randomized bloc design with 40 replications, one plant per replicate.
The seeds, prior to seeding in plastic trays (15 30 10 cm) containing 3 kg of Plantmax substrate, were sterilized
with 90% alcohol and sodium hypochlorite solution.
Each tray was composed of eight lines and each line consisted of 10 plants,
totaling 80 plants per tray.
The 149 treatments included 148 isolates of rhizobacteria and a control (trial drenched with water).
The bacterial suspension was adjusted to 550 nm (A550 = 0.1, corresponding
to 108 CFU per mL) absorbance and applied by drenching the soil (100 ml/tray), 7 days after sowing or 15 days before inoculation with the pathogen.
Seven days after drenching the soil, 40 plants of each treatment were evaluated for plant height (PH),root length (RL), total biomass (TB) and root biomass (RB).
The data were subjected to cluster analysis using average values of each individual and the degree of similarity was obtained by the standard Euclidean distance. The classes obtained were subjected to analysis of variance (ANOVA) and means compared by Skott–Knott test at 5% probability using the software SPSS version 16.0.