Evaluating the potential of plant growth promoting cyanobacteria as inoculants for wheat

Diazotrophic heterocystous cyanobacteria are known to possess the ability to form associations with vascular/non-vascular plants and produce growth-promoting substances. Most of the work on cyanobacterial inoculants has been focused on rice and other crops have received little attention. Our investigation was directed towards evaluating the potential of three cyanobacterial isolates from the rhizosphere of wheat, with emphasis on their plant growth promoting activity in pot culture experiments. All treatments were taken up in sterile soil, under controlled conditions of National Phytotron Facility, IARI and in the Glasshouse, using unsterile soil. The treatments in which all the three-cyanobacterial isolates were applied along with 1/3 N + P + K gave statistically equivalent results as compared to application of with full dose of chemical fertilizers in terms of grain yields. Significant enhancement in microbial biomass carbon in the treatments was observed at mid-crop and harvest stage, over uninoculated controls. Field level evaluation of these strains and testing under different agro-climatic conditions will help to further evaluate their agronomic efficiency and utility in integrated nutrient management of wheat crop.