Growth and yield improvement of maize by ACC deaminase producing bacteria under dry soil conditions

Abstract

The beneficial effects of plant-microbe interactions have been widely studied. This study aimed to examine the ability of ACC deaminase producing bacteria to improve maize plant growth and yield under dry soil conditions. The study consisted of laboratory analyses, a greenhouse trial, and field experiments. Eight strains of Pseudomonas and Bacillus from previous studies were formulated into four groups of bacterial consortia (PC1, PC2, PC3, and PC4) in peat-based carriers. The bacteria were evaluated for their ability to grow in osmotic stress conditions using Polyethylene Glycol. Greenhouse experiment tested the consortia to improve maize growth in soil with 50, 75, and 100% water-filled pore space (WFPS). A field experiment was conducted in a farmer's field using bacterial consortia in combination with organic fertilizer. The results showed that most bacterial strains were able to grow in osmotic stress conditions up to -2.0 MPa. Under different WFPS levels, the four consortia tested appeared to prevent maize from further stress of water shortages, although not significantly different from the uninoculated. The highest increase of maize yield under field soil condition was shown by plants inoculated with PC3 consortium. Therefore, the PC3 consortium needs further evaluation as a promising biofertilizer for dry soil conditions.