Bradyrhizobium-based biofertilizer for rice growth promotion and yield enhancement
Biofertilizer technology using Bradyrhizobium spp. rhizobia to promote rice growth, anticipate flowering, and increase yield by up to 27%. Validated in both laboratory and field trials with commercial strains of B. japonicum, B. elkanii, and B. diazoefficiens, offering a sustainable alternative or complement to chemical fertilizers in rice cultivation.
Overview
This technology leverages well-characterized legume-symbiont bacteria—specifically commercial strains of Bradyrhizobium japonicum, B. elkanii, and B. diazoefficiens—as biofertilizers for rice cultivation. While Bradyrhizobium species are traditionally known for forming nitrogen-fixing nodules on soybean, research has demonstrated their capacity to live as endophytes or root-associated bacteria in rice, promoting plant growth without nodule formation. Field trials have shown that inoculation with the best-performing strains can increase rice yield by up to 27% (approximately 1,000 kg/ha) compared to uninoculated controls. The technology offers rice growers a sustainable input that can reduce dependence on chemical fertilizers while maintaining or improving productivity.
Technical specifications
Key features:
- Uses commercially available Bradyrhizobium strains originally developed for soybean inoculation
- Promotes rice growth through increased biomass production and earlier flowering
- Validated inoculation protocol: seed immersion for 1 hour in bacterial cultures with 5% sucrose as sticking agent
- Recommended field plot configuration: 5 x 2 m plots with 5 rows spaced 20 cm apart at 400 seeds/m² density
- Compatible with standard weed management practices (e.g., Chyalofop-based weed control)
- Measured parameters included plant length, dry weight, days to fifth leaf, time to flowering, aerial biomass at harvest, yield, and thousand-grain weight
Growth promotion effects observed:
- Significant increases in plant length and dry weight at 60 days post-inoculation
- Anticipation of flowering time
- Higher aerial biomass at harvest
- Yield improvements up to 27% over uninoculated controls
Technology readiness level
The technology has been validated at laboratory scale and in field trials, demonstrating consistent positive effects on rice growth and yield across multiple parameters. Future validation is planned to optimize the technology under varying fertilizer regimes (0, 20, 50, and 100% of standard fertilizer rates) and under both flooded and non-flooded conditions, with an estimated timeline of one year. This ongoing work aims to define the best management practices for integrating Bradyrhizobium inoculation into diverse rice production systems and to clarify the conditions under which the biofertilizer can partially or fully replace chemical fertilizer inputs.
About ICGEB
The International Centre for Genetic Engineering and Biotechnology (ICGEB) is an intergovernmental organization dedicated to advanced research, training, and technology transfer in life sciences and biotechnology. Operating through state-of-the-art laboratories in Trieste, Italy; New Delhi, India; and Cape Town, South Africa, the ICGEB conducts high-level research in fields such as biomedicine, crop improvement, environmental protection, biopharmaceuticals, and sustainable energy. It functions as a global scientific hub that integrates molecular and cellular biology expertise with international cooperation, working in alignment with the United Nations Common System to foster scientific development and capacity building.
The organization serves its nearly 70 member states by bridging the gap between scientific innovation and practical application. By fostering human capital through fellowships and training, and by transferring biotechnological solutions to industry—including diagnostics, vaccines, and agricultural innovations—the ICGEB helps member countries address challenges in disease management, food security, and climate change. Its work is critical for developing nations and emerging economies, as it promotes self-reliance through local production processes and collaborative scientific diplomacy, effectively utilizing science to drive sustainable economic and social progress.
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