GENETICALLY MODIFIED CROP PLANTS
Biotechnology is providing us with a wide range of options for how we can use agricultural and commercial forestry lands. The cultivation of genetically modified (GM) crops on millions of hectares of lands and their injection into our food chain is a huge global genetic experiment involving all living beings. Considering the fast pace of new advances in production of genetically modified crops, consumers, farmers and policymakers worldwide are challenged to reach a consensus on a clear vision for the future of world food supply.
Genetically Modified Organisms (GMOs) are being made by inserting a gene from an external source such as viruses, bacteria, animals or plants into usually unrelated species. Biotechnology has granted us the ability to overcome insurmountable physiological barriers and to exchange genetic materials among all living organisms. Concerning bacteria, the ability to genetically modify plants depends on obtaining genetically identical populations and readily manipulating DNA. The use of recombinant DNA technology has the potential to allow the creation of an organism which is desired and designed by human. According by Halford, N.G, Shewry, P.R, genetically Modified crop means any crop containing or derived from a genetically engineered organism.
Another method is to culture plants from totipotent cells found in plant meristems. These plant cells can divide and differentiate into the various types of specialized cells. In a test tube, plant cells will divide and form an undifferentiated callus. When hormones in the culture medium are adjusted, the callus will sprout shoots and roots and eventually develop into a plantlet that can be transplanted to soil. To clone a plant - perhaps a plant with new genes - the growing callus is simply subdivided.
Agrobacterium has been used as an intermediate organism for transferring a desirable gene into plants (Caiping, M.A, Stauss, S.H, Meilan, R.) This has been a successful method for modification of trees and cereal crops. Biolistic transformation is a physical method by which the genes of interest are bombarded into the plant cells and DNA-coated beads are usually used as carriers (Lee, Y.S, Wetzel, E.D, and Wagner N.J.)
Electroporation is another technique which facilitates the in-corporation of genes into the host genome. This method is convenient for plant tissues without cell walls. DNA enters the plant cells through minute pores which are temporarily caused by electric pulses. These holes can be also created by microscopic crystals. Unlike electroporation, the most recent technique which consists of microinjection is a direct introduction of DNA into genome. Antisense technology is also a useful method for deactivation of specific genes such as those responsible for softening of fruits and fighting against plant viral infections.
Marker genes are often included in DNA constructs so that plants that have acquired the novel DNA can be selected. In plants, marker genes include those for herbicide resistance. It is claimed that this herbicide is relatively non-toxic and readily deactivated and degraded in the soil (Padgette et al, 1996). Plants that grow in the presence of the herbicide are assumed to possess the transgene of interest. The transgenic plant embryos are cultivated in tissue culture. Once mature plants are obtained they are evaluated for the activity of the introduced gene, any unintended effect on plant growth, and product yield and quality. The ability of the gene to be expressed in subsequent plant generations is also evaluated.
The advent of GM crops provides new opportunities for increasing agricultural production and productivity, enhancing nutritional value, developing and delivering pharmaceuticals and vaccines, and feeding the world. A common approach to thinking about the ethics of the genetic engineering of food crops and the appropriate regulatory environment is by evaluating safety and potential risks and benefits.
The Genes may "escape" and find their way into other members of the species or other species. Just imagine the trouble if herbicide-resistant genes found their way into weeds. Another risk is that the GM crops could compete or breed with wild species threatening biodiversity and monogenetic crops may not react sufficiently to environmental stresses, posing the danger of a reenactment of Ireland's potato famine. There is the potential that allergy-producing genes will be inserted into unrelated foodstuffs. Since GM foods are not labeled, a person could suffer a potentially fatal allergic reaction, e.g., an allergenic Brazil nut gene was transferred to a soybean variety, but the resultant modified crop was never released to the public. Economically, small-scale farmers could be negatively impacted by the market dominance of a few powerful seed companies. Some might be worried about the potential loss of traditional farming practices such as collecting, storing, and replanting seed. Another risk that might be encountered is that the proprietary nature of biotechnology may slow basic research, and patent protection may hinder the entry of GM foods into developing countries as has been the case with pharmaceuticals. Pusztai and many more scientists around the world are warning that genetic manipulation can increase the levels of natural plant toxins or allergens in foods (or create entirely new toxins) in unexpected ways by switching on genes that produce poisons (Pusztai, 2001).
There are potential benefits to agricultural productivity through the development of crops more resistant to pests, disease, and severe weather, decreasing the risk of devastating crop failure. With the improvement of productivity, it could result in more food from less land and a decreasing reliance on the cultivation of marginal land. Genetically engineered pest and disease resistance could reduce the need for pesticides and other chemicals, thereby decreasing the environmental load and farmer exposure to toxins. Genetic engineering could be used to remove genes associated with allergies, e.g., the blocking of the gene that produces the allergenic protein in peanuts. The insertion of genes into crops such as rice and wheat can enhance their nutritional value, e.g., Golden Rice. Genetic modification could be used to produce healthier foods, e.g., by eliminating Trans fats or caffeine for example. It could also be used to develop pharmaceuticals and vaccines in plants, decreasing the risk of adverse reactions and enabling faster vaccination of large populations.
In my opinion, GM foods have the potential to solve many of the world’s hunger and malnutrition problems, and to help protect and preserve the environment by increasing yield and reducing reliance upon chemical pesticides and herbicides. I think the government too has many challenges ahead, especially in the areas of-safety testing, regulation, international policy and food labeling. I also think that genetic engineering is an inevitable wave of the future and that we cannot afford to ignore a technology that has such enormous potential benefits. However, we must proceed with caution to avoid causing unintended harm to human health and the environment as a result of our enthusiasm for this powerful technology.

References
Caiping, M.A. Stauss, S.H. Meilan, R. Agrobacterium-mediated transformation of the genome Sequenced polar clone nisqually-1 (Populus trichocarpa) Plant Mol Biol Rep.
Halford, N.G, Shewry, P.R. Genetically modified crops: methodology, benefits, regulation and Public concerns.
Lee, Y.S. Wetzel, E.D. Wagner, N.J. The ballistic impact characteristics of Kevlar® woven fabrics impregnated with a colloidal shear thickening fluid. J Mater Sci. 2003; 38(13):2825 2833.
Padgette, S.R. Taylor, N.B., Nida, D.L., Bailey, M.R., MacDonald, J., Holden, L.R. and Fuchs, R.L. (1996).The composition of glyphosate-tolerant soybean seeds is equivalent to that of conventional soybeans. Journal of Nutrition, 126: 702-716.
Pusztai, Arpad. (2001). Genetically Modified Foods: Are They a Risk to Human/Animal Health? BioScience Productions, Inc