GM Crops-poster

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GM Crops-poster

Post by chousta on Sun Aug 17, 2008 3:46 pm

"Genetically modified organisms already help us to reduce pesticide use on cotton crops, and grow better canola crops. The benefits are greater than any risk".

This is meant to be in the form of a poster, thus I will employ headings.

  • GM crops are currently grown by 8.5 million farmers in 21 countries, where 90% of the farmers using the GM technology live in developing countries. Five countries (USA, Argentina, Brazil, Canada and China) are growing nearly 95% of the total area of these crops and there are four main GM crops that are grown worldwide.

    There are four main GM crops that are grown worldwide with soybean occupying most of the global biotech area (60%), followed by maize (24%), cotton (11%) and oilseed rape (5%). Herbicide tolerance
    is the dominant GM trait that is deployed in soybean, maize, oilseed rape and cotton and grown on 71% of the global biotech crop area. Insect resistant Bt-crops (maize and cotton) account for 18% of the
    global biotech crop area while stacked genes for herbicide tolerance and insect resistance (both in cotton and in maize) occupy 11%.

    Genetic engineering is commonly offered as a hope to improve crop production efficiency by enhancing crop tolerance to various abiotic stresses such as drought, salt and water (Yamaguchi T, Blumwald E (2005). Developing satlt-tolerant crop plants: challenges and opportunities. Trends in Plant Science, 10;615-620).

Motivations of farmers to adopt GM crops
  • The primary motivation for farmers to adopt the currently available GM crops is an expected increase in the profitability compared with conventional cultivars. Farmers can benefit from the adoption of GM crops if they are able to spend less money on chemicals and less time and effort applying them. Where GM crops provide more effective protection from pest and weed damage, farmers profit from higher yields and reduced risk of crop losses. Apart from these direct economic benefits, GM crops may further have indirect benefits for farmers such as improved soil quality due to reduced soil compaction and erosion, reduced water requirements for pesticide spraying, and reduced exposure of farmers and farm workers
    to pesticides (Brookes G, Barfoot P (2005) GM crops: the global economic and environmental impact-the first nine years 1996-2004. AgBioForum, 8:187-196).

Insect resistant GM crops
  • Studies on the economic impacts of insect-resistant GM crops are revealing benefits for farmers, most of all where yields are hampered by high pest or weed incidence or where the development of resistant pests impedes the use of pesticides (FAO 2004, Raney 2006). The benefits related to the adoption of Bt-crops may comprise both higher yields and significant reductions in pesticide use for some crops . The use of Bt-crops can lower costs by reducing the application of insecticides for pest control.
    Because chemical insecticides are generally not as effective as the control achieved with Bt-crops, yield losses are lower in Bt-crops than in insecticide treated crops. Bt-crops provide a relatively simple and reliable pest control option, because the plant is constantly expressing the insecticidal protein throughout the growing season, whereas the efficacy of insecticide treatments is often lowered due to unfavourable weather conditions and difficulties in assessing the right application time.

    Bt-cotton varieties had higher average yields, lower pesticide use and higher net returns than their conventional counterparts in all of the developing countries where studies have been undertaken (Raney T (2006) Economic impact of transgenic crops in developing countries. Current Opinion in Biotechnology, 17:174-178).

Potential environmental impacts of GM crops
  • Direct effects could result from the particular nature of the genetic change, i.e. from the resulting genotype and phenotype of the crop modified. GM crops could be able to hybridize with sexually compatible wild relatives and these could subsequently suffer an increased risk of extinction. Introduced genetically modified traits could make a crop more likely to be more persistent (weedy) in agricultural habitats or more invasive in natural habitats. Transgenic products, especially toxins produced to be active against certain pests, could be harmful to organisms that are not intended to be harmed.

Genetically modified Bt-crops

  • Insect resistance conferred via expression of various Cry-proteins from B. thuringiensis is by far the most common insecticidal protein that has been engineered into plants and is up to now the only one that is commercially used in GM crops (James 2004). Bt-genes have been engineered into a large number of plant species such as maize, cotton, potato, tomato, rice, eggplant and oilseed rape (Ely 1993, Shelton et al. 2002, de Maagd 2004). However, at present, genetically modified Bt-maize and Bt-cotton are the only crops that are commercially cultivated.

Ecological benefits of GM crop cultivation
  • GM-crops have been adopted for commercial cultivation by farmers in a number of regions over the last decade, as farmers expected potential benefits compared to conventional crops. Conventional crop protection methods relying on chemical pesticides have damaged agricultural land and the environment (see chapter 5). In addition, soil cultivation practices such as tilling have largely contributed to soil degradation by increasing erosion, nutrient loss and degradation of biological processes (Tilman et al. 2002, Ammann 2005). The introduction of GM crops has helped to reduce some environmental impacts of conventional crops and farming methods.




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Re: GM Crops-poster

Post by Alla on Tue Aug 19, 2008 2:35 am

This looks fine to me.

Good luck!


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