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What ails Bt cotton?

(Tuesday, March 18, 2003 -- CropChoice news) -- Debashis Banerji, Hindunet: The claim of the genetic engineering industry to precision, predictability and safety is not backed by its own experiences or by the science of genetics.

EXACTLY A year ago, the Genetic Engineering Approval Committee (GEAC) of the Union Ministry of Environment approved Bt cotton for cultivation in India. Monsanto, the U.S. agrochemical giant which provided the seeds, claims that more than 50,000 farmers planted Bt cotton in over 40,000 hectares. The experience of these farmers has however been extremely uneven, with reports of crop failure and disappointments from all over India.

Farmers have clearly found the seeds too expensive. Their per hectare cost is, after all, four times that of non-Bt seeds. And the yields have been reported to be less than half of those promised by the company. Bt is not engineered to produce higher yields. Indeed, the world-over, there is no commercially released transgenic crop that has been modified to give better productivity. Acreage under genetically-modified (GM) crops comprises mainly herbicide-tolerant (85 per cent) and some pest-resistant (15 per cent) crops (Current Science, Feb. 2003). Bt cotton is also aimed at substantially reducing pesticide costs. But this has not happened either. Bt plants are engineered only to resist bollworm attack. Farmers continue to complain of sucking pests such as aphids, jassids and white mosquitoes. And even bollworm resistance has been generally poor. Bt cotton is an instance of the plant acting as pesticide. If the plant does not grow well, the toxin inside it will not be produced at the lethal level required to kill the bollworm.

Bt plants engineered in the cool climes of the U.S. have not grown well in the harsh drylands of India. Especially when grown by small farmers, who are hardly in a position to set aside land for "refugia" prescribed by the company. Farmers have also complained about the quality (texture and length of fibre) of Bt cotton.

Some of the most startling evidence of Bt failure comes from a report commissioned by the GEAC, following widespread complaints of sudden collapse of the crop in the Mandleshwar block, Khargone district, Madhya Pradesh. The seven-member team of scientists comprised a cotton pathologist, physiologist, agronomist, entomologist, soil scientist and a plant breeder from the Jawaharlal Nehru Agricultural University of western M.P. It found large-scale evidence of wilting and drying of Bt cotton plants at the peak bolling stage, accompanied by leaf-drooping and shedding, as also forced bursting of immature bolls. Much lesser evidence of the same was found in non-Bt plants. In direct testimony to the complete failure of the Bt strategy of planting non-Bt "refugia," it was found that refuge plants were doing much better than Bt plants! Through microbial and nutrient studies of the soil, the team carefully ruled out the possibility that the wilting was due to a microbe (such as the fungus, Fusarium) or some nutrient deficiency. A decisive indication of a deeper malady is provided by its most dramatic finding that in a large number of cases, where two seeds were sown at a single dibbling point, only one Bt plant wilted, while the other remained healthy. The report suggestively proposes that a "genetically controlled physiological disorder" may be responsible.

It is crucial that instead of either celebrating or mourning this failure, we try and understand it in scientific terms. Could it be that the failure of Bt cotton yet again illustrates the fact that genetic engineering as practised today is based on an over-simplified understanding of the "central dogma" of molecular biology proposed by Francis Crick in 1958? Ignoring all scientific developments in the field since then? Continuing to harbour the illusion that the genome of an organism fully and exclusively determines its inherited traits? Completely ignoring the latest discoveries of molecular biology, taking which into account would undermine the very enterprise of the genetic engineers?

Over the last 30 years, culminating most decisively in the Human Genome Project (1990-2001), fundamental research in molecular biology has raised difficult questions about this overly deterministic view of the genetics of life. The Human Genome Project revealed that the difference in the number of genes across species is too small to explain their vastly diverse features. And even more recent research reported in Nature suggests that it could be the little explored RNA-based networks of gene regulation that are critical to understanding these variations. Merely inserting genes may, therefore, not be enough to produce the trait one desires.

Not just that, it may also be unexpectedly dangerous. Contrary to the claims of genetic engineers, the interplay between the alien gene and the genome of its host transgenic plant is inherently unpredictable. Belgian researchers recently found that inserting an alien gene had inadvertently modified the genome of the host plant of Monsanto's transgenic soyabean. This abnormal DNA was large enough to produce a new, potentially harmful protein (P. Windels et al, 2001). Problems have occurred the other way round as well. Kohli et al report in the Proceedings of the U.S. National Academy of Sciences that in some transgenic rice plants, the enzymes had rearranged the nucleotide sequence of the alien bacterial gene with quite unforeseeable consequences. And no attempt is being made to monitor such eventualities either. No tests are being conducted to show whether the transgenic plant is producing a protein with the same amino-acid sequence as the original bacterial protein. Nor are GM companies being asked to provide information on the biochemical activity of the alien gene, that would help track unexpected impacts. It is no surprise then that Bt cotton crops in India have shown such wildly varying results.

This may also explain why 99 per cent of the acreage under transgenic crops is still limited to just four countries worldwide, with the U.S. (where the GM companies are based) alone accounting for nearly 70 per cent of this area. We must also note the significant fact that more than 80 per cent of GM acreage in the U.S. is occupied by the herbicide-tolerant soyabean. Monsanto first provided American farmers with a herbicide to clear the soya fields of weeds. When this herbicide started killing the crop itself, the company provided farmers with soyabean that had been genetically modified to "tolerate" the herbicide. In this way, it was able to maintain sales of both its herbicide and its GM soya! What relevance can such crops have for Indian soya farmers?

Meanwhile, evidence on dangerous consequences of genetic engineering continues to accumulate, confirming theoretical apprehensions. In a paper entitled "Don't Clone Humans" (Science, 2001), Jaenisch and Wilmut provide chilling evidence of development failure in clones before or immediately after birth. They report how even apparently normal clones show kidney or brain malformations. A high frequency of enlarged hearts, gastric ulcers, arthritis and renal disease has also been found in genetically-modified pigs. And the December 2002 issue of Nature brings the sad news that a child, being treated with gene therapy for the life-threatening Severe Combined Immunodeficiency Disease (SCID), has developed leukaemia. It appears that the corrective gene inserted into the child's body unexpectedly activated another gene, causing one of his cells to proliferate uncontrollably.

The claim of the genetic engineering industry to precision, predictability and safety is not backed by its own experiences or by the science of genetics. Indeed, our understanding of genomics remains quite rudimentary. It would be best, therefore, that while building the basic blocks of this science, we proceed with abundant caution in its technological applications. Placing life firmly before profits.

(The writer, a plant physiologist by training, participated in the early efforts, in the 1960s, at understanding regulation of gene expression, at the Roswell Park Memorial Cancer Research Institute, Buffalo, New York.)