A Roman farmer Varro (1st Century BC.) is reported to have stated "Agriculture is a science which teaches us what crops should be planted in each kind of soil, and what operations are to be carried out, in order that the land may produce the highest yields in perpetuity" (Prof G T Scarascia Mugnozza - personal communication). Realizing this goal will call for continuous improvements in technology without associated ecological or social harm. In the Presidential Address to the Agricultural Sciences Section of the Indian Science Congress, held at Varanasi in January 1968, I gave the following description of the implications of unsustainable agriculture (Swaminathan, M.S., 1968 and 1993).
Exploitive agriculture offers great dangers if carried out with only an immediate profit or production motive. The emerging exploitive farming community in India should become aware of this. Intensive cultivation of land without conservation of soil fertility and soil structure would lead, ultimately, to the springing up of deserts. Irrigation without arrangements for drainage would result in soils getting alkaline or saline. Indiscriminate use of pesticides, fungicides and herbicides could cause adverse changes in biological balance as well as lead to an increase in the incidence of cancer and other diseases, through the toxic residues present in the grains or other edible parts. Unscientific tapping of underground water will lead to the rapid exhaustion of this wonderful capital resource left to us through ages of natural farming. The rapid replacement of numerous locally adapted varieties with one or two high-yielding strains in large contiguous areas would result in the spread of serious diseases capable of wiping out entire crops, as happened prior to the Irish potato famine of 1854 and the Bengal rice famine in 1942. Therefore the initiation of exploitive agriculture without a proper understanding of the various consequences of every one of the changes introduced into traditional agriculture, and without first building up a proper scientific and training base to sustain it, may only lead us, in the long run, into an era of agricultural disaster rather than one of agricultural prosperity.
Since then, there has been extensive research on the development of gene deployment strategies to match the physiologic races of pathogens, integrated pest and nutrient management systems, and other forms of environment-friendly technologies. What is the role of transgenic crops in such a quest for sustainable advances in productivity?
There is now considerable controversy on methods of assessing risks and benefits in relation to transgenic or genetically modified (GM) crops. It is becoming increasingly clear that scientific data alone cannot allay ecological, economic, health and ideological apprehensions. Hence there is need to adopt a "hasten slowly" attitude in relation to the spread of GM crops, particularly those intended for human consumption. Hasten we must in terms of scientific research, but slowly in terms of covering large areas with transgenic crops until the various doubts are cleared. The Cartagena Protocol on Biosafety represents the first step in developing internationally agreed guidelines for undertaking risk-benefit analyses in a manner which inspire public confidence.
There are many potentially valuable applications of GM technologies in tropical agriculture, where biotic and abiotic pressures are high (Swaminathan, 1982). The transition from Mendelian to molecular breeding represents a shift from generalized to precision breeding. Precision farming is an important component of sustainable agriculture. What role can precision breeding play in taking the eco-farming movement forward? The following are a few of the major scientific issues needing particular attention.
- Soil Health Care: Maintenance of soil health requires attention to the physical, chemical, micro-biological and erodability characteristics of the soil.
- Water Quality: The quality of irrigation water, with particular reference to salt concentration is important in relation to crop growth.
- Plant Health Care: Steps will have to be taken to protect crops from the triple alliance of weeds, pests and pathogens. The pest pressure is particularly high in tropical and sub-tropical agriculture, since crops as well as alternate hosts are available in the field, particularly throughout the year.
- Genetic Homogeneity: Experience has shown that genetic homogeneity enhances genetic vulnerability to pests and diseases. Monoculture of transgenic crop varieties over large areas will enhance prospects for both the breakdown of resistance and the outbreak of pest epidemics.
- Abiotic stresses With intensive agriculture, problems of salinization and waterlogging and pollution are increasing in intensity. Bio-remediation techniques will hence become increasingly important. Droughts, floods, cyclones and other natural calamities pose additional threats to crop security. The consequences of potential changes in climate as a result of global warming are yet to be understood fully but it is clear that anticipatory research should be initiated to meet potential adverse changes in temperature, precipitation, sea level and ultraviolet-B radiation.
- Post-harvest Management: Uniform ripening, uniform skin color, processing and keeping quality, capacity to withstand transportation over long distances are all becoming important in the market, particularly in vegetables, fruits and flowers. Globalization of trade is opening up new markets for agricultural produce, but markets are also getting to be very choosy in terms of quality of the produce.
Thus, there will be need for genetic material which can help to reduce or eliminate dependence on market-purchased chemicals on the one hand, and enhance adaptation to market preferences on the other. Research on bio-remediation techniques will have to be stepped up to clean up problems arising from soil and water pollution. It is not surprising that the very first patent given to any living organism was for a micro-organism developed by genetic engineering by Dr Ananda Chakrabarty for cleaning up pollution caused by oil spills (Chakrabarty. 1981).
Blending of recombinant DNA technology and organic farming methods:
For every problem, there is a solution. Methods are being developed to find substitutes for antibiotic markers in recombinant DNA experiments. Also, techniques which help to be as precise as possible in the transfer of alien DNA are being standardized. It is likely that most of the current biosafety and environmental concerns associated with GM crops will be satisfactorily addressed scientifically during the next few years, so that precision breeding becomes an important component of an economically and ecologically efficient precision farming system. The following examples from the work and approach of the scientists of the M S Swaminathan Research Foundation will help to illustrate the power of blending traditional practices with frontier technologies.