3 Myths about Genetically Modified Crops

Genetically modified oilseed rape, one of the four main commercial GM crops. Photograph: David Levene

Genetically modified oilseed rape, one of the four main commercial GM crops. Photograph: David Levene

The debate about GM crops has reached a new level with many countries deciding on its fate. Among all this shrill and cacophony about it, we indeed have been fed many myths about it. Scientific American published a nice article on it some days ago, tiled – 3 Myths about Genetically Modified Crops . It looked into some detail about the 3 most important myths.

Lets have a look, shall we ?

Myth 1: GM crops have bred superweeds

Verdict: FALSE

This issue has been quite a contentious issue for more than a decade now.

US farmers had widely adopted GM cotton engineered to tolerate the herbicide glyphosate, which is marketed as Roundup by Monsanto in St Louis, Missouri. The herbicide–crop combination worked spectacularly well — until it didn’t. In 2004, herbicide-resistant amaranth was found in one county in Georgia; by 2011, it had spread to 76. 

Many scientists, and even some of my colleagues have argued that use of GM crops which are herbicide resistant are responsible for the evolution of herbicide resistance in many weeds.

Twenty-four glyphosate-resistant weed species have been identified since Roundup-tolerant crops were introduced in 1996.

However, herbicide resistance has been a problem for farmers regardless of whether they plant GM crops or not. For more see this chart on the rise of super-weeds:

‘The rise of superweeds’  Source: Scientific American

‘The rise of superweeds’
Source: Scientific American

So, blaming just the increased use of GM crops wont solve the problem of these super-weeds.

Myth 2. GM cotton has driven farmers to suicide

Verdict: FALSE

Now this has been a big news item in India recently when a leading rights activist and environmental campaigner Vandana Shiva alleged that some 270,000 farmers have committed suicide ever since GM crops have been used. Bt cotton which has a gene from the bacterium Bacillus thuringiensis has been planted in India and has been the major bone of contention in India.

Seeds initially cost five times more than local hybrid varieties, spurring local traders to sell packets containing a mix of Bt and conventional cotton at lower prices. The sham seeds and misinformation about how to use the product resulted in crop and financial losses. This no doubt added strain to rural farmers, who had long been under the pressures of a tight credit system that forced them to borrow from local lenders.

This claim was however refuted by researchers at the International Food Policy Research Institute in Washington DC, who scoured government data, academic articles and media reports about Bt cotton and suicide in India. Their findings, published in 2008 and updated in 2011, show that the total number of suicides per year in the Indian population rose from just under 100,000 in 1997 to more than 120,000 in 2007. But the number of suicides among farmers hovered at around 20,000 per year over the same period.

Suicide Rates and GM crops Source: Scientific American

Suicide Rates and GM crops
Source: Scientific American

The important thing to note here, is that the focus of argument in India has shifted from a balanced discussion on the various ways technology can benefit us to calls for outright bans on using it. This would never solve the issue but aggravate it.

Myth 3: Transgenes spread to wild crops in Mexico

Verdict: UNKNOWN

We finally come to another issue about how transgenes have spread to far-off maize fields in Mexico. What started all of it was:

In 2000, some rural farmers in the mountains of Oaxaca, Mexico, wanted to gain organic certification for the maize (corn) they grew and sold in the hope of generating extra income. David Quist, then a microbial ecologist at the University of California, Berkeley, agreed to help in exchange for access to their lands for a research project. But Quist’s genetic analyses uncovered a surprise: the locally produced maize contained a segment of the DNA used to spur expression of transgenes in Monsanto’s glyphosate-tolerant and insect-resistant maize.

Now, as GM crops are not approved in Mexico, the only possible source of such transgenes could only have come from GM crops imported from the United States for consumption and planted by local farmers who probably didn’t know that the seeds were transgenic. When the results were published it brought a furore in Mexico with people arguing for and against the issue. Ever since, few detailed studies have been done on the spread of transgenes via GM crops.

In 2003–04, Allison Snow, a plant ecologist at Ohio State University in Columbus, sampled 870 plants taken from 125 fields in Oaxaca and found no transgenic sequences in maize seeds.

But in 2009, a study led by Elena Alvarez-Buylla, a molecular ecologist at the National Autonomous University of Mexico in Mexico City, and Alma Piñeyro-Nelson, a plant molecular geneticist now at the University of California, Berkeley, found the same transgenes as Quist in three samples taken from 23 sites in Oaxaca in 2001, and in two samples taken from those sites in 2004.

In another study, Alvarez-Buylla and her co-authors found evidence of transgenes in a small percentage of seeds from 1,765 households across Mexico.

However, some scientists argue that transgene spread could in effect have a neutral or even a positive effect on local crops.

In 2003, Snow and her colleagues showed that when Btsunflowers (Helianthus annuus) were bred with their wild counterparts, transgenic offspring still required the same kind of close care as its cultivated parent but were less vulnerable to insects and produced more seeds than non-transgenic plants.

In the end, i would quote something from the article here:

Tidy stories, in favor of or against GM crops, will always miss the bigger picture, which is nuanced, equivocal and undeniably messy. Transgenic crops will not solve all the agricultural challenges facing the developing or developed world, says Qaim: “It is not a silver bullet.” But vilification is not appropriate either. The truth is somewhere in the middle.

What in fact, would be beneficial for ending the food insufficiency problems would be develop GM crops which would have more protein content, or even essential animal proteins or could produce various other required molecules in our body. These would benefit us in more ways than by simply developing GM crops for resistance to insecticides/ herbicides. The industry needs to look at developing a holistic view of GM crops and instead of creating shrill noise, detractors should sit together with the scientists from academia/industry,policy makers and industry honchos to use technology for our benefit.

For further reading:

1). Bt Cotton and Farmer Suicides in India: An Evidence-based Assessment, Guillaume Gruèrea & Debdatta Senguptaa,The Journal of Development Studies,Volume 47, Issue 2, 2011.

2). Field versus Farm in Warangal: Bt Cotton, Higher Yields, and Larger Questions, Glenn Davis Stone, World Development,Volume 39, Issue 3, March 2011.

3). Economic impacts and impact dynamics of Bt (Bacillus thuringiensis) cotton in India, Jonas Kathage and Matin Qaim, PNAS, 2012.

4). Are GM Seeds to Blame for Indian Farmer Suicides?, Adam Pugen, Feb 2013, The International.


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