Application of ACC-deaminase containing rhizobacteria with fertilizer improves maize production under drought and salinity stress

Maize (Zea mays L.) has a lot of dietary and industrial value around the globe and its yield potential is being extremely affected by abiotic stresses i.e., drought and soil salinity/sodicity etc. However, damaging effects of abiotic stresses can be ameliorated by the combined application of plant growth promoting rhizobacteria (PGPR) and mineral fertilizers. Therefore this field trial was designed to explore the effect of PGPR containing ACC deaminase (1-aminocyclopropane-1-carboxylate deaminase) alone and in combination with mineral fertilizers on yield and nutrient uptake of maize under drought in saline held. Two PGPR strains S1 (Pseudomonas syringae) and S2 (Pseudomonas fluorescence) were applied to the maize seeds in separate and along with full and half dose of recommended NPK fertilizers. Drought stress was imposed generally on whole experiment at tasseling by withholding irrigation up to -50% field capacity (FC) level. The PGPR strains significantly improved the yield of maize when applied alone and further promising results were obtained when applied with mineral fertilizers. Maximum increase in number of cobs per plant (19.05%), cob length (68.02%) number of grain rows per cob (25.53%), number of grains per cob (28.29%) plant height (58.14%), number of grains per cob (28.29%), 1000-grain weight (35.92%) and grain yield (55.14%) was observed by the combined application of PGPR strains and full dose of recommended fertilizers over un-inoculated control and without mineral fertilizers application. Moreover combined application of PGPR strains and mineral fertilizers notably improved the nitrogen (N), phosphorus (P) and potassium (K) contents of grains and stalk of maize not only over control (un-inoculated seed and without mineral fertilizers application) but also over alone application of PGPR strains, and half and full dose of mineral fertilizers application as well. In conclusion, the PGPR strains containing ACC-deaminase activity along with full dose of artificial fertilizers improved the maize productivity due to notable expansion in yield related traits and nutrient uptake under dual stress conditions i.e., drought and soil salinity/sodicity.