GM cotton - here, there... nowhere

February 2013

Cotton Field
Cotton field. Picture by Aileen's Pics on Flickr
Mexico is the centre of origin of domesticated cotton. Clearly, steps to protect wild cotton's natural diversification are critical for conservation and future breeding.

Despite this, GM cotton has been cultivated in the north of the country since 1996, and 21 gene transformation events have been approved there (5,985 permits to sow GM cotton were issued in the first 12 years).

Genes can escape through pollen and seeds. Because cotton plants are mainly self-pollinating and the two species grown commercially in the USA can't hybridise, there's little opportunity for gene movement through pollen. However, seeds have plenty of potential for dispersal: they survive much longer than pollen and can be moved far and wide by water, weather and birds; once the cotton fibre has been removed, the seeds end up as truckloads of animal feed (on their way into the human food-chain) travelling the highways.

In 2011, a paper was published on the movement of transgenes from biotech crops into wild populations of cotton in Mexico. Noting the “simplified and typically unrealistic population models” used to assess gene flow in previous studies, the authors used more sophisticated modelling based on landscape genetics.

Samples of wild cotton plants were taken during 2002-2008, and tested for active expression of common transgenes. Four transgenes were identified: three ''Bt' insecticidal genes and one herbicide tolerance gene. Four out of the eight populations sampled tested positive for GM protein. Of these four, the three populations closest to GM cotton plots were 58.3-67.6% contaminated. The fourth, which was 755 kilometers from a GM source was, surprisingly, 29.5% contaminated. These are very significant levels of pollution.

It seems that the initial spread of these transgenes occurred through seed dispersal. After this, the artificial DNA has repeatedly recombined during reproduction and spread through pollen.

Ominously, some plants had stacked events not contained in any commercially available event, and one plant was found to be expressing all four artificial genes. This indicates that the original transgenic events are being altered in the wild in unpredictable ways. It also means that the researchers will have underestimated the extent of the pollution, because they were only looking for intact genes which were actually expressing themselves. Rogue artificial DNA which is not producing a protein in the plant, but could nevertheless interfere with the healthy functioning of its natural DNA, wasn't sought, and may even form the bulk of wild cotton's actual genetic pollution.

The conclusion reached was that self-pollination and geographical barriers hinder, but can't prevent, gene flow: the invaluable wild germ-plasm of cotton in Mexico is in danger.

Is the risk of compromising our future access to a huge wild-cotton gene-pool, that should be the heritage of future generations, worth it?

In India, policy makers would say 'yes' to this question. They have hailed Bt cotton as a success story. But Greenpeace has a different version. The 'success' of the GM cotton has been brought about by “fake farmers” vouching for GM cotton crops they never grew and by persuasive local promotions that have lured many real farmers into using the high-priced GM seed and agrichemicals needed. This has turned, for many, into a debt-trap in which some farmers have been driven to suicide.

At the start of 2012, advertisements placed by Monsanto India in a major newspaper claiming that “Bollgard (GM cotton) boosts Indian cotton farmers' income by over Rs31,500 crores” were found by the Advertising Standards Council of India to be 'not substantiated'.

By March 2012, the Indian media were reporting that:
“India's Bt cotton dream is going terribly wrong ... Cotton farmers are in deep crisis since shifting to Bt cotton ... Bt cotton's success, it appears, lasted merely five years. Since then, yields have been falling and pest attacks going up” (Zia Haq).
By November 2012, even the state government in India's largest cotton-growing area was admitting that yields of Bt cotton were down 40%. The problem has been severely exacerbated by rising prices for GM seed, fertiliser, pesticides and labour. Farmer suicides in this state have been officially reported as up by 43% (Note that the actual figure may be much higher).


There seem to be an awful lot of GM cotton plants right in the middle of our future genetic resources: this is the last place we want them. And there seem to be far too few GM cotton plants in Indian farmers' fields: where people's lives and livelihoods are dependent on them:.

The story of cotton may well herald the shape of things to come: imagine your food-supply caught in a wild GM maze it can't get out of, with crop failures at every second turn?

On the subject of gene pollution, check out WHY 'CO-EXISTENCE' IS IMPOSSIBLE - January 2013.

  • A Wegier, et al., 2011, Recent long-distance transgene flow into wild populations conforms to historical patterns of gene flow in cotton (Gossypium hirsutum) at its centre of origin, Molecular Ecology, 20
  • Yogesh Pawar, Bt failure to hit cotton yield by 40%: Govt, Daily News and Analysis,, 26.11.12
  • Rachna Arora, Advertising Standards Council of India concludes Mahyco Monsanto Biotech's claims on Bollgard are unsubstantiated, Public Awareness on Genetically Modified Foods, 12.01.12
  • Zia Haq, Ministry blames Bt cotton for farmer suicides, Hindustan Times, 26.13.12
  • The marketing of Bt cotton in India - aggressive unscrupulous and false, Greenpeace 20 .09.05
  • Sandeep Pai & Sudhir Suryavashi, Marathwada region beats Vidarbha in farmer deaths, Daily New Analuysis,, 3.03.12
  • Ashish Roy, Hard truths come to fore before panel, Times of India, 3.03.12

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