Isolation and selection of rhizospheric bacteria with biofertilizing potential for corn cultivation

Objective: To isolate and determine in a greenhouse environment the biofertilizing potential of rhizospheric bacteria associated to corn (Zea mays L.) at Campeche, Mexico.Design/methodology/approach: Rhizospheric soils were collected from two corn production zones with different management conditions. Bacterial strains were isolated from these samples and their biofertilizing potential determined by in vitro and in vivo tests. The obtained data from both tests were assessed using an analysis of variance (ANOVA) and a means comparison test (LSD, p0.01).Results: In total, 16 rhizospheric bacteria were isolated, a higher number in non-mechanized soils (n10) compared to mechanized ones (n6). In the in vitro tests, the most representative activity corresponds to nitrogen fixation (81%) attributed to a higher bacteria percentage, while the activity with lower bacteria numbers corresponds to IAA production (25%). At the in vivo tests in corn plants, the YM1 strain presented the highest fresh and dry root biomass (20 and 2 g plant1, respectively). The YM4 strain promoted greater plant height (63.33 cm), and YM5 registered the highest values in stem diameter (7.13 mm), root length (36.78 cm) and fresh shoot weight (12.03 g plant1).Limitations/Implications: Strain evaluations were limited to controlled greenhouse conditions.Conclusion: The YM1, YM4 and YM5 strains show potential for further evaluation as biofertilizers for corn cultivation under field conditions.