Abstract

REYES, Isbelia; ALVAREZ, Luimar; EL-AYOUBI, Hind  and  VALERY, Alexis. Selection and evaluation of growth promoting rhizobacteria on pepper and maize. Bioagro [online]. 2008, vol.20, n.1, pp.37-48. ISSN 1316-3361.

A group of Gram negative rizobacteria able to fix atmospheric nitrogen and to solubilize inorganic phosphate was chosen from different plant rizospheric soils of Táchira State.  Eight non-diazotrophic and seventeen dizotrophic rhizobacteria belonging to the genus Azotobacter, Azospirillum and Rhizobium were characterized using biochemical tests. The effect of these rhizobacteria was evaluated on the germination, growth and N and P uptake of pepper (Capsicum annuum) and maize (Zea mays) in greenhouse conditions. The bioinoculation effect of pre-selected strains was evaluated on seedling germination. It was found that strains 17 and 20, an Azotobacter sp. and a Gram negative rod, respectively, promoted pepper germination; while the strains 1 and 23, another Gram negative rod and an Azospirillum, respectively, promoted maize germination. In greenhouse conditions the strain 1 and Azospirillum 23 increased significantly (P≤0.05) the N uptake, and Azospirillum 23 the P uptake in maize aerial tissue; while most of the evaluated strains increased significantly (P≤0.05) N uptake in pepper. Discussion is centered on the selection of potential bioinoculants and some biological considerations related to the plant-microbe interaction.

Keywords : Azospirillum; Rhizobium; Azotobacter; bioinoculants.