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The Hindu
The Hindu
Technology
D. Balasubramanian

Improving rice yield with an additional gene

The Green Revolution of the 1960s brought about a marked improvement in the yield of agricultural crops such as rice and wheat. It was based on the use of newly developed high-yielding crop varieties in conjunction with the intense use of irrigation, chemical fertilizers and pesticides. India saw a three-fold increase in rice yield per hectare. 

Now, fifty years later, some negative effects of this intense methodology are becoming apparent — nitrogen fertilizers and agrochemicals pose environmental hazards; water is often in short supply; and agricultural soil is increasingly fatigued.

To obtain more food for the world’s growing population, forests and grasslands would have to be converted to farms in order to produce food. This, in turn, would enormously strain our ecosystems.

40% yield increase

A possible way out of this conundrum has been suggested in a recent publication by Wei et al., “A transcriptional regulator that boosts grain yields and shortens the growth duration of rice”, which appears in the journal  Science, July 22, 2022. Erik Stokstad, a reporter for  Science points out in the same issue that “supercharged biotech rice yields 40% more grain”.

This report points out that giving a Chinese rice variety a second copy of one of its own genes has boosted its yield by up to 40%. When a second copy of a single gene (called  OsDREB1C) is added to rice, it improves photosynthesis and nitrogen use, speeds up flowering and absorbing nitrogen more efficiently — offering larger and more abundant grains. The change helps the plant absorb more fertilizer, boosts photosynthesis, and accelerates flowering, all of which could contribute to larger harvests.

Rice exports

India is the world’s largest exporter of rice. It exported 18.75 million metric tons to over 150 countries during the year 2021-22, thereby earning $6.11 billion. This is a vast improvement from what it did a few years ago. As Adhikari et al. point out in 2016 (Export of rice from India; performance and determinants.  Agri. Econ. Res. Review), it is clear that with growing demand in the coming years, strategies should be found to increase the production and export of rice.

Vietnam turns out to be the second most producer of rice, and it produced 6.5 million tonnes in 2021-2022. It has to be much more than the 18.75 million tons for India to continue and expand its role as the world’s largest producer and exporter of rice.  It is here that the above-mentioned paper from China by Wei  et al. in  Science is of value.

Gene modulation

A key point is that the researchers have added the same gene again, and not any foreign one. This is best described as genetic modulation. It is not a genetic modification (GM) and neither is the result a transgenic plant, carrying elements from another donor. 

This is particularly relevant to India, which must aim to continue its world position in the production of rice and marketing. An article published on June 16 in  The Wire (‘India’s GM crops regulation should be based on a gene’s effects, not its source’) points out that “India has exempted crops with certain kinds of genetic modifications from the regulations previously imposed on the commercialisation of all genetically modified crops”.

For example, BT cotton involves the transfer of the gene from the bacterium called  Bacillus thurigiensis (BT) to be transferred to normal cotton. India’s Agriculture Ministry has pointed out in 2019 that they have allowed transfer of this foreign gene to normal cotton, produce the BT cotton, which is then manufactured and sold both in India and abroad.

Likewise, an article in  Business Standard points out that India will import 1.2 million tons of genetically modified (GM) soyabeans for livestock feed. Now, if the ministry allows the import of GM soyabean from abroad, why should it not allow the manufacture of this in India itself?

On the other hand, what the  Science authors had done above is to add an extra copy of an already existing ‘native’ gene ( OsDREB1C) in rice, and not a foreign one, as in the case of BT cotton or BT soyabean. India has some excellent rice researchers located in Andhra Pradesh, Karnataka, Punjab and Haryana, and genetic engineers in several laboratories across the country.

The Ministry of Agriculture can come together with the Department of Biotechnology (DBT) and nutritionists from the Indian Council of Medical Research (ICMR) can support these researchers to augment India’s role as the major rice exporter in the world.

dbala@lvpei.org

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