Biotechnology

Traditionally biotechnology has been associated with the centuries’ old practice of fermentation used in the making of bread, beer, and spirits. A modern, more inclusive, definition encompasses any technological application that uses biological systems, living organisms, or their derivatives to make useful products or processes.34 Driving modern biotechnology is the revolution in cellular and molecular biology that occurred in the second half of the twentieth century.35 In particular, it uses our knowledge of DNA and RNA to identify the genetic basis of useful traits in animals and plants.

Modern plant breeding—derived from the discovery by Gregor Mendel of the particulate nature of inheritance and developed over much of the last century—has transformed agricultural production through the selection and crossing of crop varieties (see Chapter 9). However, it is often an uncertain and lengthy process: Discovery of mutations with desirable properties is serendipitous, and incorporating them into new varieties involves many crop generations and hence years of careful breeding, sometimes with limited success.

An example of successful, conventional breeding is the development of “quality protein maize” (see Chapter 9). A discovery in the 1960s of maize mutants with high levels of desirable amino acids started a breeding program that, after several decades, has successfully incorporated these desirable traits into better maize varieties for developing countries.36 By contrast, biotechnology makes this process speedier and more effective.

The most prominent form of crop biotechnology is the production of genetically modified (GM) crops. The process is described in detail in Chapter 9. In brief, a gene of potential usefulness is isolated and then inserted into the cell of a crop plant by a process of transformation, either by using a naturally occurring bacterium (Agrobacterium tumefaciens) that infects plants or by coating gold particles with the gene and shooting the particles into crop plant cells with a gene gun. The transformed

Box 7.6 Bt Cotton

Bt cotton contains a gene from a common soil bacterium, Bacillus thuringiensis, that produces an insecticidal protein in the plant that kills major cotton pests such as the cotton bollworm (Helicoverpa armigera) and pink bollworm (Pechnophora gossypiella). These are serious worldwide pests of cotton, maize, vegetables, and other crops; their long-distance migrations and the variety of their hosts can lead to large outbreaks. The cotton bollworm is estimated to cause annual crop damage of as much as $2 billion across the globe.37

Nearly thirteen million “small and resource poor” farmers are now growing Bt cotton.38 Burkina Faso, the largest cotton producer in Africa, adopted Bt cotton on a commercial scale in 2008. A year later it was being grown on over 100,000 ha, with yields up to 50 percent higher than conventional cotton and with the number of pesticide sprays reduced from an average of eight to at most two.39 A World Bank review of the benefits of Bt cotton in Argentina, China, Mexico, India, and South Africa showed increases in yields of between 11 percent and 65 percent, and increased profits as high as 340 percent with significantly reduced use of pesticides and pest management costs (Table 7.1).40

Table 7.1 Economic and environmental benefits of growing Bt cotton in developing countries

Benefit

Argentina

China

India

Mexico

South Africa

Added yield (%)

33

19

26

11

65

Added profit (%)

31

340

47

12

198

Reduced chemical sprays (number)

2.4

2.7

2.2

Reduced pest management costs (%)

47

67

73

77

58

Source: World Bank41

cells are then cultured and grown into whole plants that are tested in the greenhouse to ensure that the transferred gene, the transgene, functions properly. Not all transgenic plants will express the trait or gene product well. But once the trait is stable, it can be bred using conventional plant breeding methods into cultivars with adaptation to the environmental conditions where the crop is produced.

One example is a crop, such as cotton, engineered to express a bacterial gene that controls certain insect pests, so reducing the need for harmful synthetic pesticides (Box 7.6).

However, despite these well-documented benefits, recombinant DNA or GM technology is controversial and has attracted considerable opposition, especially in Europe. I discuss this more fully in Chapter 9.

 
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