Effects of super absorbent polymer and plant growth promoting rhizobacteria on yield and yield components of maize under drought stress and normal conditions

In order to study the effects of super absorbent polymer and plant growth promoting rhizobacteria (PGPR) on yield and yield components of maize (double cross 370), the experiment was done in Karaj region/Iran in 2009. The experiment was conducted as a randomized complete block design with 4 replicates and in two separate experiments under drought stress and normal conditions. Seven different treatments have been studied in this experiment, including: T-1: Grain inoculation with biofertilizer (Azospirillum lipoferum + Pseudomonas putida), T-2: Applying super absorbent polymer as gel on a row, T-3: Applying super absorbent polymer as powder on a row, T-4: Grain inoculation with biofertilizer (A. lipoferum + P. putida) and applying super absorbent polymer as powder in rows, T-5: Grain inoculation with biofertilizer (A. lipoferum + P. putida) and applying super absorbent polymer as gel in rows, T-6: Mixing biofertilizer (A. lipoferum + P. putida) with super absorbent polymer (as gel) and applying in rows and T-7: Non-application of super absorbent polymer and biofertilizer (Control). The result of this experiment showed that drought stress reduced grain yield, biological yield, number of grains per row, number of grains per ear and harvest index. But no significant decrease observed on stem and leaf dry yield. The application of super absorbent polymer (powder or gel) and inoculation of grain with biofertilizer (A. lipoferum + P. putida) increased grain yield and biological yield in both stress and normal condition. Co-application of super absorbent with biofertilizer (T-4, T-5, T-6) in compare with T-7 treatment in both drought stress and normal condition increased grain yield, but under normal condition in compare with T-2 treatment and under stress condition in compare with T-2 and T-3, it did not increase grain yield, biological yield and other traits.