BIOTECHNOLOGY IN IMPROVING CROP PLANTS
Introduction
In a world where the population is growing by millions every year, feeding everybody is a problem which is becoming more and more difficult to solve. With the aid of biotechnology, scientists can produce new strains of plants where once there would have been little hope of a successful harvest.
Animal diseases can be controlled by biotechnology. As a result of genetic engineering, animals can be more productive and farmers can reduce their use of pesticides and fertilizers. Microbes too will be a major source of nourishment. Biotechnology is making rapid advances towards solving the food problem.
Improving Crop Plant
For generations, farmers have been selecting and breeding crop plants to produce more food. Today, genetic engineering gives agricultural scientists a valuable new tool. They are able to produce plants that can live in places where the climate does not normally allow plants to survive. It maybe too cold, for example, and microbes that prevent ice formation on plants have been developed. We may also have plants that can produce their own fertilisers and resist the attacks of insects and viruses.
Plants need nitrogen to build up vital components inside their cells, such as proteins and DNA. Animals can obtain their nitrogen by eating plants or other animals, but plants get their nitrogen from the soil. Although air contains about 80% nitrogen and 20% oxygen, for most forms of life nitrogen gas is useless. Only when it is ‘fixed’ in the form of ammonia (NH₃) or nitrates can it be used by plants for growth. This process is called nitrogen fixation.
Farmers can add nitrogen fertilisers to the soil, but this is expensive. And when it rains some of the fertiliser is washed into rivers causing pollution, including unwanted growth of microscopic water plants such as algae.
Peas, beans and clover have been known to restore fertility to soil where a crop such as wheat plants. The bacteria take nitrogen directly from the air and ‘fix’ it into a form that plants can use for growth. Food crops such as soya beans and peanuts can also fix nitrogen from the air but unfortunately cereals like wheat and barley cannot. Genetic engineering was used to alter these nitrogen-fixing bacteria so that they will be able to live in the roots of cereals and act as a built-in fertiliser factory.
Genetic engineering is also being explored as a way to improve food value of plants to make them more nutritious to eat. Plant cells, unlike animal cells, have a thick, rigid cell wall. If this wall is dissolved using enzymes, we are left with a plant cell without its ‘jacket’ called a protoplast. Protoplasts from cells of different plants can be fused together to form a new plant called ‘hybrid’.
Potato and tomato plants have been joined in this way to form a ‘pomato’ plant. This only works because the tomato and the potato belong to the same family of plants. Some types of plant cell can grow a whole plant from just the one cell. This is very useful for plant breeders since it means that thousands of identical plants ( or clones) can be grown from the cell of a single plant that has been selected. This can be achieved for a number of vegetables, including carrots and potatoes, as well as for ornamental plants such as orchids.
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Source : Hobsons Scientific
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