Bt cotton ineffective against bollworm: research

Updated: Aug 1 2005, 05:30am hrs
Recent research findings on Bt cotton have placed the countrys regulatory authority, Genetic Engineering Approval Committee (GEAC) in the dock. Based on a series of experiments, a team of scientists from Nagpur-based Central Institute of Cotton Research (CICR), have proved that the Bt cotton becomes ineffective in its resistance to bollworm after 110 days.

GEAC is slated to meet on August 10 and take up the matter. The civil society organisations, who have claimed that Bt cotton has failed to produce the desired results, are now up in arms demanding a review of the decision.

Bollworms cause extensive damage to the cotton crop. With a view to make the cotton plant resistant to bollworms, transgenic technology was applied by inserting the gene from a soil bacteria, Bacillus thurigiensis (Bt). This inserted gene allows the plant to produce Cry1Ab protein which is toxic to bollworms.

However, a team of scientists from CICR, led by Keshav R Kranthi, have recently found that the resistant power in cotton plant remains only for 110 days, after which the crop can be exposed to bollworm attacks. The Cry1Ac level declines as the plant grows and is found to drop below its lethal level of 1.9 mg within 110 days after sowing.

In our next meeting, we may discuss the findings of the paper published in Current Science, said a senior GEAC member. The study further said that toxin expression were lowest in the ovary of flowers and rinds of green bolls which are the most favoured sites of bollworm attack.

The study was published in the July 25 edition of Current Science. Current Science also published in May 25, 2003, a similar study conducted by a team of scientists in the University of Agricultural Sciences, Dharwad.

The decline in resistant power means that the farmer has to apply more chemical pesticides to save his crop. Already, the cost of Bt cotton seeds are high and added to this, he incurs additional costs on pesticides. Eventually, he lands up in heavy debts, a researcher said.

Those farmers, who hope that Bt cotton can be a miracle and, therefore, do not apply heavy doses of chemical pesticides, are at a loss, said the director of Secunderabad-based Centre for Sustainable Agriculture (CSA), Dr GV Ramanjaneyulu. The very fact that scientists do not have control over toxin expression in plants shows that transgenic technology is imprecise and unpredictable, he said.

He said that CSA conducted studies on each of the three years of commercial cultivation of Bt cotton in India. All the results proved that Bt cotton growers incurred losses. In contrast, the farmers growing non-Bt cotton, following the procedures of organic farming and applying bio-pesticides, reaped good profits, he said. u

In the past three years of commercial cultivation of Bt cotton, several other NGOs like Gene Campaign, Research Foundation for Science, Technology and Ecology, and Deccan Development Society, conducted studies and came out with similar results. These NGOs and farmers organisations like Bharat Krishak Samaj had cautioned GEAC to withdraw approval to Bt cotton.

However, GEAC, this year, approved 13 new varieties of Bt cotton for different regions of the country. At the same time, it banned cultivation of Mech-12 Bt in the entire south Indian region and Mech-162 Bt and Mech-184 Bt in Andhra Pradesh on receiving adverse reports from the concerned state government.