Study finds wide variety of nitrogen-use efficiency in Indian rice varieties

GGU biotechnologists discover rice varieties with varying nitrogen use efficiency, crucial for reducing pollution and improving crop yields.

Biotechnologists at the Guru Gobind Singh Indraprastha University (GGU) here have discovered a wide variation among popular varieties of rice in India in their ability to use nitrogen. This knowledge can be used to develop newer varieties that use less nitrogen and are high-yielding, thus slashing expenditure on imported fertilizers and reducing nitrogen-linked pollution.

“Cereals consume two-thirds of all urea in India, led by rice. Poor fertilizer nitrogen-use efficiency (NUE) wastes N (nitrogen)-fertilizers worth ₹1 trillion a year in India and over $170 billion per year globally,” N. Raghuram, Professor at GGU, and lead author of the paper, said, reporting these findings.

Nitrogen use efficiency refers to the yield of a crop relative to the nitrogen (natural and artificial) available to it.

“Worse, N-fertilizers are the main source of nitrous oxide and ammonia pollution of air and nitrate/ammonium pollution of water, affecting our health, biodiversity, and climate change. Yet, we don’t have a ranking of any Indian crop varieties in terms of their NUE for crop improvement by selection or breeding,” Dr. Raghuram said.

The paper was published late last week in the peer-reviewed Journal of Plant Growth Regulation.

The NUE of the best varieties were five times as much as the least, the investigation found. However, a high NUE doesn’t always mean the highest yields and farmers in India generally prefer varieties with the highest yields.

“The focus of Indian agriculture has for a long time been to solely increase yield. This was necessary during the Green Revolution but this also meant more synthetic fertilizers, more wastage, and pollution. India has tens and thousands of rice varieties but only a few are actually used and studied as part of agricultural research. To find newer crops that have improved NUE and yields, we have to have a wider approach,” Dr. Raghuram told The Hindu.