Biotechnologists detect difference in use of nitrogen by rice varieties

Biotechnologists detect difference in use of nitrogen by rice varieties

Context

Biotechnologists at Guru Gobind Singh Indraprastha University (GGU), New Delhi, have discovered significant variations in the nitrogen-use efficiency (NUE) among popular rice varieties in India.

• This research holds potential for developing new rice varieties that are both high-yielding and require less nitrogen, thereby reducing fertilizer costs and nitrogen-linked environmental pollution.

Relevance:

GS-03 (Biotechnology)

Key Findings:

• There is a wide variation in NUE among different rice varieties in India, with some varieties demonstrating up to five times more efficiency than others.
• Nitrogen-use efficiency refers to the yield of a crop relative to the nitrogen (natural and artificial) available to it.
• Despite high NUE, these varieties do not necessarily produce the highest yields, leading farmers to often prefer high-yielding varieties that may not be as nitrogen-efficient.
• Current agricultural practices focus primarily on increasing yield, leading to excessive use of synthetic fertilizers, wastage, and environmental pollution.

Significance:

• Economic Impact: Poor NUE results in significant economic losses, with nitrogen fertilizers worth ₹1 trillion wasted annually in India and over $170 billion globally.
• Environmental Concerns: N-fertilizers are major contributors to nitrous oxide and ammonia pollution, as well as nitrate and ammonium contamination in water, affecting human health, biodiversity, and contributing to climate change.
• Agricultural Sustainability: Developing rice varieties with better NUE can reduce dependency on imported fertilizers, decrease environmental pollution, and promote more sustainable agricultural practices.

Key highlights about nitrogen:

1. Essential Nutrient: Nitrogen is a crucial nutrient for all living organisms, integral to molecules like proteins, nucleic acids (DNA and RNA), and vitamins.
2. Atmospheric Abundance: Nitrogen gas (N2) constitutes 78% of Earth’s atmosphere, yet it is largely inaccessible in this form to most organisms.
3. Scarcity in Ecosystems: Despite its abundance, nitrogen is often a limiting resource in ecosystems because it must be converted into a usable form.
4. Nitrogen Fixation: The process of converting nitrogen gas (N2) into ammonia (NH3), making it biologically available, is known as nitrogen fixation, performed by certain microorganisms.
5. Major Nitrogen Transformations: The key processes include nitrogen fixation (N2 to NH3), nitrification (NH3 to nitrite and nitrate), and denitrification (nitrate back to nitrogen gases).
6. Types of Nitrogen-Fixing Organisms: These organisms can be free-living or symbiotic, aerobic or anaerobic, and phototrophic or chemotrophic, all utilizing the enzyme nitrogenase for nitrogen fixation.
7. Biological Importance: Nitrogen is found in vital compounds such as alkaloids and urea, underscoring its significance across various biological systems.

Way Forward

• A broader approach in agricultural research is needed, focusing not just on yield but also on NUE to identify and promote rice varieties that balance both.
• Improvements in NUE can be achieved through better fertilizer formulations, legume-based crop rotations, and crop management practices.
• Enhanced focus on biotechnological advancements is necessary to develop rice varieties that are both high-yielding and nitrogen-efficient, ensuring sustainable agricultural growth in India.