Role of biological preparations in enhancement of rice seedling growth and grain yield

The application of five commercial chitosan-based formulations of carefully chosen plant growth-promoting rhizobacteria developed at Auburn University, USA has previously shown demonstrable increase in the growth of nursery-raised plants such as cucumber, pepper and tomato among others. The present study evaluates the beneficial effects of the formulations on the growth of rice seedlings. Seedlings of three indica rice cultivars, IR24, IR50 and Jyothi raised in rice field soil amended with each of the formulations in a 1 : 40 (formulation : soil) ratio have shown significant two-fold increase in root and shoot length, and grain yield. The observations do suggest that application of such commercial bacterial formulations can serve as microbial inoculants for the improvement of rice growth.