Application of alginate bead encapsulated n2-fixing bacteria is improving wheat yield under drought stress

Water scarcity is one of the most pressing and threating environmental issues facing the human population. Plant growth promoting bacteria (PGPB) are presented as safe and ecological complementary solution to the food security problem along with the traditional crop breeding and genetic engineering. Plant-associated microbial communities, such as, nitrogen-fixing bacteria, improve crop productivity and provide stress tolerances for different biotic and abiotic factors. In this study, we isolated and characterized fourteen Azotobacter spp from rhizosphere of wheat plants, among these isolates; we identified the most effective plant growth promoting isolate as Azotobacter chroococcum using Bio-log identification system. The encapsulated of the A. chroococcum with sodium alginate shows beds integrity intact bacterial cells using the scanning electron microscopy. Encapsulated A. chroococcum was tested for growth promotion of wheat under different water regime at field experiments, the results indicated that encapsulated A. chroococcum was effective in lowering the harmful effect of water deficit on several wheat agronomical criteria. Wheat treated with encapsulated or liquid culture significantly diminish the reductions in relative water content recorded 66.37% and 59.23% , respectively under water defiant 80% from actual evapotranspiration plus 100% and 75% mineral nitrogen . Moreover, wheat inoculated with A. chroococcum in two forms showed reduction in proline accumulations in shoots, as well as lowest antioxidant enzymes contents. The inoculation with A. chroococcum either encapsulated or liquid culture significantly enhanced wheat grain yield and yield components, as well as nitrogen (N), phosphorus (P), and potassium (K) contents in grains of wheat under water defiant 80% from actual evapotranspiration.