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Bt Cotton Benefits Short-lived : Study

New Delhi, Feb 10 (PTI) There is some bad news for Indian farmers who have started growing a type of genetically modified cotton containing the bacillus thuringiensis (Bt) gene.

The Bt gene produces a toxin called "cry1ac" that kills the bollworms

But a study just released by entomologists at Indian Agricultural = Research Institute in New Delhi has cast doubts on the long-term benefits of Bt cotton. It has found that the protection afforded by bt gene is at best = for six years.

The study by K Chandrasekar and G T Gujar has found that the bollworm develops "31-fold resistance to the toxin "cry1ac" within six = generations." The bollworms also developed cross-resistance to two more toxins called "cry1aa" and "cry1ab."

Cotton farmers in the country spend Rs.1200 crores on pesticides to = protect their crops from this single pest.

What this study means is that cotton farmers may have to go back to spraying pesticides after six seasons unless scientists come out with = bt cotton hybrids that produce a high dose of the cry1ac toxin.

The scientists say their findings "mandate the necessity of bt = resistance management." One way of doing this is by ensuring that each farmer = allots a part of his land for non-bt crops -- a requirement unlikely to be = followed by farmers with small land holdings.

Development of resistance to bt cotton is not unknown. In China the expected life of bt cotton was found to be 7 to 10 years in areas under = Bt cotton exceeding 70 per cent.

Three cotton hybrids carrying the Bt gene are being marketed in India = by a company jointly set up by the US multinational Monsanto and its Indian partner Maharashtra Hybrid Company in Mumbai.

In just two years the area under the officially approved Bt cotton had trebled from 72000 hectares to 2.16 million hectares while an illegal variety of bt cotton covers nearly 90 per cent of the cotton area in Gujarat. (PTI) J sp sp 02101451 D