LAUSR

BACKGROUND Plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi have the ability to enhance growth, fitness and quality of various agricultural crops, including cowpea. Yet, field trials confirming benefits of microbes in large-scale application using economically viable and efficient inoculation methods are still scarce. Microbial seed coating has a great potential for large-scale agriculture through the application of reduced amounts of PGPR and AM fungi inocula. Thus, in this study, the impact of seed coating with PGPR, Pseudomonas libanensis TR1 and AM fungus, Rhizophagus irregularis (single or multiple isolates) in grain yield and nutrient content of cowpea under low-input field conditions was evaluated. RESULTS Seed coating with P. libanensis + multiple isolates of R. irregularis (coatPMR) resulted in significant increases in shoot dry weight (76%), pod and seeds number per plant (52 and 56%, respectively) and grain yield (56%), when compared with non-inoculated control plants. However, seed coating with P. libanensis + R. irregularis single-isolate (coatPR) did not influence cowpea grain yield. Grain lipid content was significantly higher (25%) in coatPMR plants in comparison with control. Higher soil organic matter and lower pH were observed in the coatPMR treatment. CONCLUSIONS Our findings indicate that cowpea field productivity can be improved by seed coating with PGPR and multiple AM fungal isolates under low-input agricultural systems. This article is protected by copyright. All rights reserved.