Auxin Producing Plant Growth Promoting Rhizobacteria Improve Growth, Physiology and Yield of Maize under Saline Field Conditions

Abstract

Soil salinity is one of the most widespread agricultural problems which reduce the field crop productivity. Salinity disturbs the hormonal balance in plants which results in poor growth. Use of plant growth promoting rhizobacteria (PGPR) is considered an economical and environment-friendly approach to combat salinity stress. This study was carried out to investigate the effect of auxin producing PGPR on the growth, antioxidant status and mineral content of maize (Zea mays) in salt affected soils. Rhizobacterial strains were isolated from the rhizosphere of maize growing under salt affected soil conditions. These strains were screened on the basis of auxin production and their ability to withstand salinity stress. Two stains (MA4 and MA11) which produced highest auxin and tolerated maximum salinity were selected for further evaluation in a field experiment. The results of field trial showed that soil salinity reduced the plant growth, mineral nutrient uptake and yield of maize while antioxidant activity and proline concentration was increased. However, rhizobacterial inoculation improved grain yield (31%), fresh biomass (56%) and phosphorous contents in grains (26%) while the proline concentration (41%), ascorbate peroxidase (59%) and SOD values (42%) in leaves were declined. The results of present study signify the role of auxin producing rhizobacteria under salt affected field conditions.