Title : Plant Growth-Promoting Rhizobacteria (PGPR) improve maize development under saline stress conditions: A sustainable biotechnology approach
Abstract:
Maize (Zea mays L.) is a strategic crop for global food security and a cornerstone of Mexican agriculture. However, increasing soil salinity, land degradation, and dependence on synthetic fertilizers threaten sustainable maize production worldwide. Plant Growth-Promoting Rhizobacteria (PGPR) represent an environmentally friendly biotechnology capable of enhancing crop performance while contributing to soil bioremediation and resilience under adverse conditions. This study evaluates the effect of bacterial consortia on the emergence, growth, and stress tolerance of three maize genotypes: the varieties atenco-23 and roque, and the hybrid HS-2. The research was developed in three stages. First, fluorescent bacterial strains were isolated, characterized, and evaluated under saline stress conditions using culture media supplemented with 1%, 2%, and 3% NaCl. Strains showing positive effects on plant growth were selected for greenhouse experiments. During the second stage, three bacterial consortia were inoculated under controlled conditions. Consortium 3 significantly increased emergence, vegetative development, and dry biomass in the atenco variety, while consortium 2 showed the best performance in the HS-2 hybrid compared with the control.
The third stage, currently under field evaluation, examines the effectiveness of the consortia under real saline stress conditions using wastewater irrigation containing sodium, potassium, and magnesium salts. The experimental design consists of two comparative plots (irrigated with clean water versus irrigated with wastewater) distributed across eight treatments with three replicates each. A pre-germination treatment based on potassium nitrate (KNO3) is included, resulting in a total of 24 treatments per plot. Preliminary field data confirm the outstanding performance of consortium 3 during the emergence stage in both maize varieties. Current monitoring focuses on plot uniformity, crop earliness, and chlorophyll content before and after physiological maturity, with the expectation of achieving at least a 20% increase in final yield. These findings demonstrate the strong potential of PGPR-based biotechnology to reduce agrochemical dependence, improve tolerance to saline stress, and promote more sustainable and resilient maize production systems.
