Bt brinjal too can create super weeds.

Bt brinjal too can create super weeds. 

Gene flow from a transgenic plants has remained a contentious issue. In the absence of experimental data, the task to pinpoint exactly as to how much is the potential risk, especially in centres of diversity, becomes daunting. The GM industry has often used lack of experimental data to show there is no cause for concern. It has happened in India, in the case of Bt cotton, and more recently when the moratorium on Bt brinjal came in 2010.

John Samuels of the Novel Solanaceae Crops Project, Penzance, Cornwall, UK, has raised some valid concerns, based on available data, in an excellent paper published in Trends in Biotechnology (Vol 31, Issue 6, June 2013). Admitting that transgene flow from Bt brinjal to wild, weedy and cultivated relatives is a major biosafety concern, he writes in an article Transgene Flow from Bt Brinjal: a real Risk? (URL: http://www.cell.com/trends/biotechnology/fulltext/S0167-7799(13)00068-1): "in preliminary risk assessment tests in India in 2007, only four spiny species were tested for interfertility with S.melongena  (http://www.envfor.nic.in/divisions/csurv/geac/bt_brinjal.html). They found only Solanum incanumL. (the nearest wild relative of brinjal) to be crossable; however, the production of hybrid progeny was not investigated." With such limited scientific studies available, obviously gene flow was considered to be not much of a problem. 

Citing various reasons like inadequate experimental methodologies and erroneous nomenclature of the parent species, John Samuel tells us that the biosafety implications of hybridisation remained compromised. Looking through the research data now available, he says that six wild relative species and four cultivated species have the potential to crossbred with the transgenic Bt brinjal. I have taken this table out from the article for an easy understanding. 

Table 1 Solanum species of India known to cross with brinjal

	Species	Common name	Status
	S. aethiopicum L.	Scarlet eggplant	Cultivated
	S. cumingii Dunal	Wild brinjal	Wild
	S. incanum L.	Bitter tomato	Wild
	S. insanum L.	Weedy brinjal	Wild
	S. macrocarpon L.	Gboma eggplant	Cultivated
	S. marginatum L.f.	White-margined nightshade	Wild/introduced
	S. ovigerum Dunal	Brinjal landraces	Cultivated
	S. torvum Sw.	Pea eggplant	Sometimes cultivated/introduced
	S. violaceum Ortega	Indian nightshade	Wild
	S. virginianum L.	Bitter brinjal	Wild

  
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His conclusion: "Furthermore, the risk assessment of pollen-mediated transgene flow from Bt brinjal, if cultivated in Bangladesh or the Philippines, should not rely on the inadequate, previously undertaken ERA (Environmental Risk Assessment) tests." Hope the scientists as well as the science administrators are listening. Especially in the light of latest revelations that show how super weeds are becoming a nuisance in United States and Canada. 

GM Crops: Hearing the warning bells

Environmentalists have been telling us about the presence of DDT residues in human milk and even traces of it in the blood of penguins. This tells us how widespread the use and abuse of this chemical is, but it took us more than 40 years to realise that DDT is a harmful persistent organic pollutant.

While the effort is to phase out the harmful chemical, I am worried about the growing emergence of biological toxins — like Bt — and the threat they pose to our health and environment. Newer estimates tell us that each Bt plant produces within itself a heavy dose of toxins equal to 4.2 kg per hectare, 19 times more than the average use of chemical pesticides. Still more worrisome is a recent Canadian study that shows widespread presence of Bt-related insecticides in the blood of 93% pregnant women and in 80% of foetuses.

This shocking study prompted Glenn Davis Stone, professor of anthropology and environmental sciences at the University of Washington, to ask: “What does this mean for human health impacts? Nobody knows.” That is exactly what worries the people. Why can’t scientists hold more long-term experiments to know of the potential dangers GM technology can have on human health and the environment?

Having failed to learn any lesson from the DDT debacle, the scientific community is pushing ahead for the acceptance of GM crops. So when the Supreme Court-appointed Technical Expert’s Committee (TEC) in its interim report suggested a moratorium for 10 years on field trials of GM crops till the time a regulatory mechanism is put in place, the GM industry reacted sharply.

The TEC report couldn’t have come at a better time. Only a few weeks ago, Giles-Eric Seralini, professor of molecular biology at the University of Caen, France, came out with another shocker. In a long-term study on rats for two years, he has demonstrated that when fed with GM maize and a particular herbicide, rats developed huge kidney and skin tumors, and also had digestive problems. Female rats developed fatal mammary tumours and pituitary disorders. In addition, the fatality rate was very high.

As expected, the industry reacted terming the study ‘bogus’, ‘fraudulent’ and ‘unscientific’. The rat study has shown how important it is to replicate such long-term experiments in multi-location trials. This is exactly what the TEC as well as the Standing Parliamentary Committee, which submitted its report in August, had also called for.

In case of agriculture, the claims have fallen flat. There is no GM crop in the world which increases crop productivity. US department of agriculture acknowledges low productivity of GM corn and GM soybean. The promise of reducing chemical pesticides usage has also been belied. In the US alone, pesticides use has increased by 404 million pounds between 1996 and 2011. In India, the Central Institute for Cotton Research has shown that pesticides usage in cotton has not decreased with the advent of Bt crops.

Still more worrisome is the emergence of super weeds and resistant insects. In America, more than 14.5 million acres are now afflicted with super weeds which are difficult to eliminate. As many as 23 weeds have now been classified as ‘super weeds’. Imagine the crisis that awaits farmers if GM crop field trials, without any effective regulatory system in place, continue to be allowed. A robust regulatory regime, with science-based long-term studies on the impact of GM crops on soil, animal and human health and the environment are desperately needed.

Source: Hearing the warning bells, Hindustan Times, Nov 9, 2012. 
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