Erratum to: A simple method to evaluate the number of bradyrhizobia on soybean seeds and its implication on inoculant quality control

The authors regret that an error appears in Penna etal. (2011). The fourth sentence in the section Formulation and evaluation of the selective medium "This compound was initially solubilized in 98% ethanol, sterilized using 0.2 μm filters, added to 45°C YEM medium, and homogenized to obtain a final concentration of 0,2 g.l-1 of PCNB into the P-YEM medium". Must be replaced by the following "A solution of 10% PCNB in acetone, was diluted 1/5 in Tween 80 0,5%v/v in water, sterilized using 0.2 μm filters, added to 45°C YEM medium, and homogenized to obtain a final concentration of 0,04 g.l^-1 of PCNB into the P-YEM medium".