Concerns with genetically modified cotton

For a long time, farmers have been trying to change the genetic makeup of plants. Genetically- modified cotton was first grown in the USA on a large scale in 1996. Genetically-modified cotton is the result of such efforts in which characterized genes are incorporated in a

conventional cotton plant through using recombinant-DNA technology. The required gene that is to be introduced is called a transgene and plants having a transgene are called transgenic plants. The statistics from the last 20 years showed that land under cultivation for the production of genetically-modified cotton is continuously increasing and reached around 18.5 million ha (hectare) in 2014 having a growth rate of 3-4% per annum [362]. As far as cotton is concerned crossbreeding between cotton plants having required characteristics, produces different varieties with improved fibre yield and quality and having better sustainability in temperate regions [363]. In spite of all these achievements the potential of yield increase via this traditional approach has reached a plateau that requires new genetic engineering techniques [364]. After the successful introduction of genetically-modified (GM) cotton, questions were asked about the potential impact of these crops, such as apart from whether this modified crop will

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affect only targeted insects, will it have adverse impact on climate and living creatures or not and to what extent these will be beneficial to the environment by reducing the input of synthetic chemicals used in cultivation. There seems to be a difference in opinion as far as genetic

modification of cotton is concerned. One group of people in favour including consumers, farmers and researchers is of the view that genetic modification can attribute characteristics (like pests or insects resistance) that results in less use of harmful pesticides and insecticides, further this technology can be used to promote sustainability and help to revolutionize agriculture on modern lines giving increases of yield as well as quality of cotton fibres [365,366]. However Altiere and other critics [367, 368] are of the view that there is no need for plant biotechnology as it is bad for consumers’ health, will impoverish small farmers, increase the use of pesticides and will bring about a decrease in biodiversity. This discussion is very important, especially for developing countries which have not yet decided whether to use this technology or not. Genetically-modified cotton is promoted on the basis of the following three advantages.

 Increase in the yield of cotton crop.  Increase in the income of farmers.

 Less use of pesticides (more environmentally-friendly).

Different potential risks are attached with GM cotton as compared with non-GM cotton like transgenes that offer a particular advantage but could increase invasiveness of the crop. Similarly, a high proportion of insect toxins in biologically-modified crops may cause toxic effects to other organisms or non-target insects. During the transformation stage, antibiotic- resistant genes are introduced into GM crops but the introduction of these genes can promote the development of antibiotic-resistant bacteria. It is also not clear whether current varieties of herbicide-resistant cotton and Bt cotton are more invasive than conventional varieties of cotton or not. However some varieties of cotton having novel transgenes like salt and drought tolerance which provide a selective advantage can turn out to be more invasive and could cause the development of ‘super weeds’ in the case of the gene passing to other wild relatives [369]. Different techniques have been developed in order to control migration of genes from GM crops to other wild relatives like seed sterility, induction of pollens and manipulation of crops to produce GM seed without fertilization [370,371]. Tabashnik [372] says that the insect-resistance management techniques (IRM) that are used in Bt crops are effective in managing and

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approaches have been effectively used in Bt cotton, however the most widely-used approach is high dosage [373,374]. However, it is clear that biotechnology has revolutionized the agriculture industry through genetic modification with better resistance towards insects. One such example is transformation using insecticide-resistance genes from Bacillus thuringiensis [375, 376]. These kind of modifications have shifted cultivation away from the previous heavy dependence on chemical pesticides.

Eliminating or reducing the use of some kinds of pesticide may have some benefit, however it can also have adverse effects on profit and yield. It is possible to find adverse environmental impact by discarding one pesticide and using another one. Hence for analysing environmental stability, the toxic load should be calculated and compared with current practices and through the introduction of other technologies for enhancing plant resistance [377]. Furthermore, the

prospect of transferring specially-extracted genes to other wild varieties and to microbes is a serious concern from the environmental point of view. On the one hand GM cotton ensures sustainability because it is pest resistant and decreases the load of pesticides on the fields, whilst on the other hand, some industrial agriculture reform organizations are trying to prove it has bad impacts on the environment and human health. Whatever theory is correct it is clear that

biologically-modified cotton is gaining popularity on a global scale in spite of the high prices of GM cotton seeds [378].