Rice plants applied with biofertilizers composed of four bacteria are healthier than those fertilized with other forms as shown in a recent study conducted by Philippine Rice Research Institute (PhilRice).
Mac Michael Rubio, one of the researchers, said four strains of rhizobacteria were found to enhance rice growth. The strains were identified and selected using a molecular technique while soil samples were collected from major irrigated lowland rice fields in Central Luzon.
“Rhizobacteria naturally exist in the soil surface of the plant root system. They aggressively colonize the root system to support the plant’s growth through different mechanisms. The bacteria fix nitrogen; solubilize phosphorus, potassium, and zinc; and produce plant hormones and enzymes. [However, we need good combination to optimize effect],” Rubio explained.
Rubio and his team selected four rhizobacteria strains, combined them and formulated a biofertilizer, which they tested under screen house condition.
Results showed that the combination supported better rice growth than individual bacteria application and zero bacteria treatment when applied to NSIC Rc 160 after seed soaking.
At vegetative stage, the team observed 50% increase in the number of tillers. Rice plants with rhizobacteria-based fertilizer produced 15-19 tillers while the untreated plants had 7-8 tillers.
The biofertilizer also resulted in high resistance to rice blast and sheath blight – diseases which reduce yield by 50-85%.
Rubio said the biofertilizer produced Ammonia, which helps supply adequate amount of nitrogen and Indole-3-acetic acid, which is necessary for plant growth regulation.
The biofertilizer was also found to provide the plants with good amount of siderophore, which supports iron uptake of plant, and of phosphate, which helps in the easy absorption of phosphorus.
Despite results, the researchers have yet to disclose the strain combination pending patent application. Studies to validate the effects of biofertilizer under actual field condition are also on-going.
The research, authored by Mac Michael Rubio, Dr. Truong Hoai Xuan, and Dr. Arlen A. Dela Cruz, won 3rd place in the scientific poster competition during the 45th Philippine Society of Biochemistry and Molecular Biology Annual Convention and is funded by Department of Science and Technology – Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development.