Technologies of microbial inoculation in rice - A Review

The conventional techniques for free cell inoculation, though inexpensive and easy to inoculate have limitations. Selection of carriers for the inoculants is crucial to support the storage of inoculants for marketing and the delivery of suitable amount of microorganism in good physiological condition. To overcome the limitations of scarcity of suitable carrier materials as well as to check the uncontrolled release of bacteria, encapsulated microorganism or alignate beads and irrigation based inocula delivery system have been developed. Apart from common inorganic, organic and polymeric compound used as carriers for microorganism delivery, research also being pursued to develop bacterial biofilms and nanoparticle based carriers. Idea of inoculation of bacteria into the plant cell suspension and their regeneration, though in infant stage, also seems to be one of the future possibilities. On the other hand, multi-strain inoculation claims to be better over single-strain inoculation. Critical and comprehensive analysis of the current knowledge of these technologies with emphasis on rice has been discussed in this review.