Relevance of genetic engineering applications in agriculture
Biotechnology is a field of science in which living organisms are used as tools in generating a product and a process such as fermentation where enzymes are used to generate a fermented product is a type of biotechnological process.
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The technique has advanced into modern biotechnology where the structure of genes have been identified and individual genes can be isolated and introduced into another organism across species barrier, a process known as genetic modification. This article places emphasis on the applications of genetic engineering and its relevance to agriculture.
The growing population is fed through agriculture. Since ancient times, biotechnology has contributed to agriculture and currently, genetic engineering is facilitating agriculture in several ways as elaborated below.
Genetically engineered crops
Crop production is normally challenged by pests and diseases attacking plantations, and ultimately reducing productivity. Genetic engineering has discovered a gene in soil bacteria called Bacillus thuringiensis (Bt), which has protein that forms crystals only in the guts of specific insects in the family of butterflies and moths.
The gene coding for this protein has been successfully isolated and introduced into some crops. Genetically modified crops are thus known as genetically engineered crops. This way when the insects feed on these crops which have been genetically engineered, the gene is activated in the guts of the pest, forming crystals which ultimately cause the death of the insect.
These genetically engineered/modified crops are therefore said to be pest resistant, as they use this mechanism to manage insect pests. There is therefore no need to spray your fields with insecticides to deal with associated pests preventing possible overspraying of crops and ultimately chemical residues in crops. Some examples of genetically modified crops are soybean, maize and cotton found in North and South America, Asia, Africa and some parts of Europe.
The use of such crops reduces the spraying of broad-spectrum insecticide on plantations which kills both beneficial and non-beneficial insects, pollute the environment as well as have adverse effect on the health of farmers. Similarly, farmers use herbicides to control weeds on their farms. Not using these herbicides means they have to cultivate the land or till the soil by weeding continuously.
The disadvantages include high labour cost (drudgery), distortion in the carbon content of the soil, organic matter and populations of other organic organisms, including earthworms, ants and birds nesting in the soil. The use of herbicides, instead of weeding, however, is not beneficial to some crops as the herbicides kill those crops as well as the weeds, limiting the use of herbicides. Genetic engineering has identified genes responsible for herbicide resistance in bacteria and this has been isolated and engineered into crops generating herbicide resistant crops. Thus plantations can be sprayed with herbicides without causing any harm to crops, but eliminate only target weeds. Some examples of herbicide-resistant GM crops are maize and cotton.
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Another modification that is being developed is the introduction of a gene responsible for converting atmospheric nitrogen into a form that can be readily used by plants. Although the atmosphere is made up of approximately 78 per cent nitrogen, it is in a form that cannot be utilised readily by plants. However, a naturally occurring rhizobium bacterium is found in the soil, which converts atmospheric nitrogen into a form usable by plants. These nitrogen-fixing bacteria are also found naturally occurring in the legumes of certain plants such as soybeans and peanuts.
Naturally, this mechanism exists for beans and soybean where they associate with soil bacteria and form special organs called nodules in which the atmospheric nitrogen is trapped and converted to a form that plants can utilise for growth and development. Without this system, tonnes of inorganic nitrogen fertilisers have to be applied to the soil to facilitate growth since crops normally use the nitrogen available in the soil. These GM crops, when developed, will require little or no nitrogen fertilisers which could result in reduction in the funds needed to purchase costly fertilisers.
Commercial value
Genetically modified crops have been growing on the fields and utilised on commercial basis since 1996, hence 20 years of utilisation. Below is information indicating the adoption of this technology.
The following crops have been genetically-engineered:
Alfalfa, apple, Argentina canola, bean, carnation, chicory, cotton, creeping bent grass, eggplant, eucalyptus, flax, maize, melon, papaya, petunia, plum, polish canola, poplar, potato, rice, rose, soybean, squash, sugar beet, sugar cane, sweet pepper, tobacco, tomato and wheat.
There are 37 traits that have been introduced into the various crops. These include abiotic stress tolerance, altered growth/yield, disease resistance, herbicide tolerance, insect resistance, modified product quality and pollination control systems.
The global market value of biotech crops keeps increasing on yearly basis. In 2014, it was estimated to be US$15.7 billion, representing 22 per cent of the US$72.3 billion global crop protection market in 2013, and 35 per cent of the US$45 billion global commercial seed market. Of the biotech crop market, US$11.3 billion (72 per cent) was obtained in industrialised countries while US$4.4 billion (28 per cent) was obtained in developing countries. The accumulated global value of biotech crops since 1996 is estimated at US$133,541 billion.
The information above is indicative of advancements that have been made in the application of biotechnological tools in the development of beneficial crops. Most of the traits worked on are of benefit to the farmers in the line of production. Other traits that will be of nutritional benefit to the consumer have to be explored to produce genetically engineered crops with enhanced nutritional benefits. Research in Africa and Ghana to be specific may not be able to directly use the genes identified by the research groups that have developed the herbicide and insect-resistant crops because of specificity imposed on the engineering to the gene. Specificity includes the species of target insect and weeds. However, these identified genes can provide immediate leads to us unearthing similar genes in our ecosystem.
This article was written by Marian D. Quain, Charles Afriyie-Debrah, Ruth N.A. Prempeh and James Y. Asibuo, CSIR-Crops Research Institute, Kumasi.