CORRELATION BETWEEN SCREENING PROCEDURES TO SELECT ROOT ENDOPHYTES FOR BIOLOGICAL CONTROL OF Fusarium verticillioides IN Zea mays L.

LILIA CAVAGLIERI, ALEJANDRA PASSONE AND MIRIAM ETCHEVERRRY

BIOLOGICAL CONTROL

Elsevier

Lugar: Londres (Inglaterra); Año: 2004 vol. 31 p. 259 - 267

1049-9644

Biological control is an alternative to pesticides for protection against crop diseases. A key to progress in the field of biological control to protect maize against Fusarium verticillioides is to select in vitro the best agent to be applied in the field. This research was undertaken to evaluate the correlation between different screening methods and to suggest an adequate procedure that could be used to select bacterial agents with potential biocontrol against Fusarium verticillioides in the maize rhizosphere. The results show a extensive Pearson correlation coefficient analyses between different screening procedures carried out for Arthrobacter spp., Azotobacter spp, Pseudomonas spp .and Bacillus spp. paired with 13 Fusarium verticillioides strains isolated from maize endorhizosphere. The following screening methodologies were correlated: niche overlap index (NOI), indices of dominance, growth rate, lag phase, antibiosis and fumonisin production. It was observed that NOI and antibiosis methodologies did not show correlation and were used to choose the best bacteria to apply under greenhouse conditions. Azotobacter armeniacus RC2 showed a NOI>0.9 and inhibited all Fusarium verticillioides strains assayed. Seed maize bacterization with Azotobacter armeniacus RC2 at 106 and 107 inoculum level resulted in significantly lower values of F. verticillioides counts compared to the control without bacteria at the root levels assayed. Analysis of variance indicated that there were significant interactions between two fungal repression assays. Antibiosis assays significantly correlated with greenhouse conditions (p<0.01) at two inoculum levels tested. Therefore the selection system adopted was adequate to choose the best bacterial biocontrol agent. The application of this methodology shows a way to outline the best biocontrol candidate.