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A cautious approach needed while going about genetic modification

Genetic yield is a factor that does not only revolve under a single gene

A cautious approach needed while going about genetic modification

Instead of being swayed by hyperbole, perhaps GEAC has a lot to learn from this young researcher. In a Twitter thread that followed, Khaipho-Burch had blasted the scientific claims calling these ‘misleading’

When I read reports that researchers at the Julius Kuhn Institute (JKI) in Germany have developed varieties of a scab resistant apple, and that too by conventional breeding techniques, I was reminded of my visit, some decades ago, to the famed John Innes Centre in Norwich in the United Kingdom.

Accompanying a handful of farmers and civil society representatives on a visit to the acclaimed plant and microbial institute, I vividly recall an introductory briefing by a scientist.

“Conventional plant breeding is much more dangerous than genetic engineering,” she stated, and added: “Genetic engineering only touches a couple of genes at best and does not disturb the genetic makeup of the plant.”

Being myself a plant breeder by training, I asked “why is that I was never told that the science I was engaged in was so dangerous?”

Probably not expecting any plant breeder to be in that group, the scientist was taken aback, and then recomposing herself went on to defend her statement. Nevertheless, this only showed how an effort was made to run down conventional plant breeding so as to justify how useful genetic engineering is.

So when scientists reported the development of a new apple variety – Pia41 – that could resist the fungal attack on apple, remaining scab free during five years of its research trials, it comes us a renewed hope for Indian apple growers, who have constantly been applying huge quantities of fungicides to keep the dreaded fungus at bay.

Not only being scab-free, the variety is also professed to have “a green-yellow skin, juicy, crunchy pulp and a sweet taste with an intense aroma.”

Now let me revert back to the point I was trying to make. The new scab-free apple variety comes at a time when after 10 years of research trials at Wageningen University in the Netherlands, wherein scientists incorporated a gene to develop scab-resistant apple variety by genetic modification (GM) in 2011. Eventually as it failed to yield any satisfactory results, the GM research trials were abandoned in 2021.

This brings me to an interesting paper by a young researcher Merritt Khaipho-Burch et al, published in the much respected multi-disciplinary scientific journal Nature (Sept 20, 2023), where she not only questions the claims of significant increases in crop yields by GM technology, but also writes, ‘Genetic Modification can improve crop yields – but stop overselling it’, asks why do scientists have to hype their claims. While it is so heartening to see a PhD student at the Cornell University questioning the claims over yield gains whereas I thought every senior scientist should have seen through it, and expressed some sort of restraint before showing exuberance that at best appear superficial.

She starts the article by what I consider as a profound statement. Saying that most scientific journals, including Nature, often talk of yield gains by 10 to 68 per cent emanating from modifying one or two genes in crops like rice, corn, tobacco and soybean, the reality is that most of these studies have been conducted in green houses or in small plots (and even in pots) and then extrapolated to show production jumps for crops grown in a hectare. “And hardly any findings have translated into yield increases on actual farms,” she emphasised. This is what GM Watch, a formidable group that keeps track of GM research, and scientist groups like Union of Concerned Scientists besides others have also been saying.

With the entire scientific community on one side, it is commendable how a researcher, still young to take on the behemoth’s in the field of genetic engineering, picked up the courage to demolish an earlier scientific paper in the esteemed journal Science by a team of Chinese scientists, led by crop physiologist Wenbin Zhou of the Chinese Academy of Agricultural Sciences. The paper had claimed yield increases of 41.3 to 68.3 per cent in rice by modifying a single gene (OsDREB1).

Simultaneously, this research article was backed by an editorial in Science magazine (Supercharged biotech rice yields 40% more grain, Science, July 22, 2022) that had claimed: “The change helps the plants help absorb more fertiliser, boost photosynthesis, and accelerates flowering, all of which could contribute to large harvests.”

These claims had made the scientific community go euphoric and some even blamed the environmentalists for stopping such spectacular gains to be achieved from GM research that could feed the rising populations. Media had taken the findings by storm, and even scientific journals were swayed by the research outcomes.

This takes me to a similar media hype created over a junk GM mustard variety in India, which claims a yield increase by about 25 per cent over a test variety that is much lower in yield performance. It is therefore important that the Genetic Engineering Appraisal Committee (GEAC), which grants approval over such exaggerated claims, revisits its approval framework for GM crops.

Let me explain how flawed the GEAC approval mechanism is. Instead of being swayed by hyperbole, perhaps GEAC has a lot to learn from this young researcher.

In a Twitter thread that followed, Khaipho-Burch had blasted the scientific claims calling these ‘misleading’. In her latest peer-reviewed paper, she says that over the years, research by plant breeders, quantitative geneticists, evolutionary biologists and plant biologists has shown that yield increases by one to five per cent, though modest, is what really makes the difference. Quoting a study published in the journal Plant Science in 2021, she showed that researchers studied the impact of 1,671 genes drawn from 47 crop species and found that only one per cent of the genes tested had the potential to impact yield, and therefore needed to be studied more.

Genetic yield is a factor that does not only revolve under a single gene. Yield is a multi-gene factor. To illustrate, in maize alone, around 20-30 genes have been instrumental in increasing plant density by 3-4 times over the past 100 years. “Yield itself is a highly complex, polygene trait – meaning that it is controlled by thousands of variants, each with a small effect.”

Not to be misled by the hyper claims, the authors have suggested a five-point criteria that researchers, reviewers and editors should ensure before buying the hype. It will be immensely useful if agricultural universities and head of the institutes in India (and also the regulatory bodies) share this paper widely and formulate a research template based on it. Let the society be well-informed.

(The author is a noted food policy analyst and an expert on issues related to the agriculture sector. He writes on food, agriculture and hunger)

Devinder Sharma
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