Controlling Maize Late-Wilt and Enhancing Plant Salinity Tolerance by Some Rhizobacterial Strains

Abstract

The effects of plant growth promoting rhizobacteria (PGPR) on decreasing maize late wilt disease caused by Cephalosporium maydis, enhancing plant tolerance to salinity stress and plant growth parameters were studied. In vitro, four out of the seven Pseudomonas fluorescens isolates and three out of nine isolates of Bacillus subtilis showed the potency to cease the growth of all target pathogens. Significant reduction in disease incidence was recorded under greenhouse and field conditions in seeds treated by PGPR strains either individually or in combination. PGPR seed coated treatments carried on biochar were the best which reduced the disease to 72% in normal soil and 70% in saline soil under greenhouse conditions, whereas, it gave 82.8% disease reduction in normal soil and 79.3% in saline soil in the field. This treatment promoted seed germination percentage, plant height, dry weight and chlorophyll levels more than other treatments. Also, seed treatments with rhizobacteria decreased the proline induction compared with untreated plants in normal and saline soil due to decrease of salinity stress by PGPR especially that carried on biochar. Under field conditions in normal and saline soil, rhizobacteria seed coating carried on biochar either alone or in combination significantly decreased disease infection and enhanced the plant yield compared with control.