Transgenics in the Indian context

GREEN REVOLUTION was a great technological success of the second half of the Twentieth century. By the introduction of scientifically bred, high yielding varieties of rice, wheat and maize in the Sixties, the overall food production in the developing countries increased with the pace of population growth. While the gains in food production provided by the green revolution have reached their ceiling, the world population continues to rise. In the decades to come, agriculture in the developing countries will be confronted with an extraordinary set of challenges such as ensuring adequate food availability for the increasing population, removal of malnourishment among children and consequent deaths and use of natural ecosystem more efficiently.

To address these needs dramatic advances are required in food production and distribution. It is not conceivable that agriculture can deliver the expected output without modern technology like biotechnology. Various terms have been used to describe this form of biotechnology including genetic engineering, genetic transformation, transgenic technology, recombinant DNA technology and genetic modification technology. Here in this article which is focused on plants and plant products, the term genetic modification technology or GM technology is used.

The genetic modification of plants involves transferring DNA (deoxyribonucleic acid), the genetic material from a plant or bacterium or even an animal, into a different plant species. Due to the advancement in molecular biology now we can identify appropriate genes determining particular characteristics and can easily incorporate into the plants we wish to modify. Although the techniques required to create GM crops are recent, genetic modification is in most respects an extension of what has been happening for the last ten thousand years.

`Unnatural' status

Introduction of GM crops into the environment and food chains has become highly controversial. The principal objections to GM crops and the food products made from them concern possible harm to human health, damage to the environment and unease about the `unnatural' status of this new technology. Despite the media hype, no real dangers related to biotech foods have ever been documented.

In the years to come food demand is expected to exceed supply. Moreover meeting the demands of a consumer society will be very difficult. The demands of consumers, growers and retailers are many and the time frame in which these have to be delivered gets shorter. Even if genetic material may be available to satisfy all these criteria, a breeding programme may take up to 20 years to achieve some of these goals. By that time the consumer demand and preference may have changed, pest and disease problems may have altered and the industry could be under threat. Thus to improve the sustainability of existing farmlands and also to improve the quality and quantity of food supply, GM technology is inevitable.

Real potential

The real potential of GM technology to address some of the most serious concerns of world agriculture has only recently begun to be explored. Certain examples show how GM technology can be applied to some of the specific problems of agriculture indicating the potential for benefits. Devastation of crops by pests is a major problem for farmers. To fight pests farmers now usually spray crops with tonnes of chemicals. There is clearly a benefit to farmers if a plant that can resist a specific pest is developed. Now papaya has been grown commercially since 1996 in Hawaii which can resist papaya-ring-spot-virus. This is a boon to farmers. Fungal blight (phytophthora infestans), fusasium wilt, bacterial rot (erwinia sp) are some of the problems facing potatoes. Now GM potatoes have been developed by the University of Victoria, British Columbia, to resist these problems. Vine weevil, a major pest of strawberry, causes damage to its root system which results in the loss of yield and ultimately death of plants. Resistance to this weevil is developed by the introduction of GM strawberries and the gene responsible is derived from tropical legume, cowpea.

Several Indian institutes and organisations (public as well as private sector) have claimed to have developed transgenic plants, which are ready for greenhouse/polyhouse evaluation and some are ready for field evaluation as well. Some of the major Indian developments up to the present time in transgenic plants are insertion of Bt toxin gene on rice by Bose Institute, Calcutta, Bt toxin gene on brinjal, tomato and cauliflower by IARI, New Delhi and Bt toxin gene on potato by CPRI, Shimla for generating plants resistant to lepidopteran pests. Snow drop (galanthus nivalis) lectin gene on chilli, bell pepper and tomato for resistance against lepidopteran, coleopteran and homopteran pests by Rallis India Ltd., Bangalore.

Another important area touched by GM technology is in the development of crops that have an inbuilt resistance to abiotic stress, thereby enabling farmers to cultivate land that is currently non-arable. A vast landmass across the globe, both coastal as well as terrestrial has been marginalised because of excessive salinity, alkalinity and arid condition. A salt tolerance gene from many cover (avicennia marina) has been identified, cloned and transferred into plants (M.S. Swaminathan Foundation, Chennai). Such plants were found to be tolerant to higher concentration of salt. The gut D gene from escherichia coli has also been used to generate salt-tolerant transgenic maize plants. An enzyme producing gene from bacteria which live in the human colon has been used to help plants survive better in desert and areas with lots of sun, by neutralising the active oxygen species (such as H{-2}O{-2}) that kill plant cells. This technology is a great boon for farmers to grow food and fruits in desert areas. In short, abiotic stress tolerant genes are a potential source for developing cropping systems for marginalised land.

Improvement of food quality

By GM technology now we are able to improve the appearance and colour of fruits, vegetables, flowers, etc., increase the shelf- life and also enhance the nutrient content of plants and foods. Now by the advancement of GM technology we can sip decaffeinated coffee. Caffeine-free coffee plants are released in Hawaii and the plants produce just 3 per cent of normal amount of caffeine. In tropical areas, rice (oryza sativa) a major staple food, is usually milled to remove the oil-rich aleurone layer that turns rancid upon storage. The remaining edible portion of rice grain, the endosperm, lacks several essential nutrients, such as provitamin A. Thus predominant rice consumption promotes vitamin A deficiency, a serious public health problem and causes half a million children to become partially or totally blind each year in different countries of Asia, Africa and Latin America. By GM technology a combination of transgenes enabled biosynthesis of provitamin A in the endosperm. This GM rice exhibits increased production of beta- carotene as a precursor to vitamin A and the seed is yellow in colour. Such ``golden rice'' may be a useful tool to help treat the problem of vitamin A deficiency in young children living in the tropics.

The current initiatives in biotechnology in India, primarily an agricultural country with a predominant population of marginal farmers, are unfortunately oriented to the needs of large scale commercial agriculture. This warrants urgent intervention for redirecting the course of investigation towards subsistent and sustainable farming. Areas like improvement of the nutritional quality of food may be given priority in biotech research. The major share of biotech research in the country is now in public sector. Although, this may slow down the pace of results, it can beneficially be utilised for catering to the needs of small farmers and countering their exploitation by `Gene Giants'. The cost factor involved GM seeds needs to be resolved intelligently to make it affordable to the farmers.

ULLAS MONY and K. RAJMOHAN

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