genetically modified crops


Presentation Description

No description available.


Presentation Transcript








GENETIC MODIFICATION Genetic modification involves the insertion or deletion of genes. In the process of cisgenesis, genes are artificially transferred between organisms that could be conventionally bred. In the process of transgenesis, genes from a different species are inserted, which is a form of horizontal gene transfer. In nature this can occur when exogenous DNA penetrates the cell membrane for any reason. To do this artificially may require attaching genes to a virus or just physically inserting the extra DNA into the nucleus of the intended host with a very small syringe, or with very small particles fired from a gene gun. However, other methods exploit natural forms of gene transfer, such as the ability of Agro bacterium to transfer genetic material to plants, and the ability of lentiviruses to transfer genes to animal cells.

Slide 6:

The first commercially grown genetically modified whole food crop was a tomato (called FlavrSavr), which was modified to ripen without softening, by Calgene, later a subsidiary of Monsanto. Calgene took the initiative to obtain FDA approval for its release in 1994 without any special labeling, although legally no such approval was required. It was welcomed by consumers who purchased the fruit at a substantial premium over the price of regular tomatoes. However, production problems and competition from a conventionally bred, longer shelf-life variety prevented the product from becoming profitable. A tomato produced using similar technology to the Flavr Savr was used by Zeneca to produce tomato paste which was sold in Europe during the summer of 1996.The labeling and pricing were designed as a marketing experiment, which proved, at the time, that European consumers would accept genetically engineered foods. Currently, there are a number of food species in which a genetically modified version exists (percent modified are mostly 2009/2010 data).

Slide 9:

Between 1997 and 2009, the total surface area of land cultivated with GMOs had increased by a factor of 80, from 17,000 km 2 (4.2 million acres) to 1,340,000 km 2 (331 million acres). Although most GM crops are grown in North America, in recent years there has been rapid growth in the area sown in developing countries. For instance in 2009 the largest increase in crop area planted to GM crops (soybeans) was in Brazil (214,000 km 2 in 2009 versus 158,000 km 2 in 2008.) There has also been rapid and continuing expansion of GM cotton varieties in India since 2002. (Cotton is a major source of vegetable cooking oil and animal feed.) In 2009 84,000 km 2 of GM cotton were harvested in India. In India, GM cotton yields in Andhra Pradesh were no better than non-GM cotton in 2002, the first year of commercial GM cotton planting. This was because there was a severe drought in Andhra Pradesh that year and the parental cotton plant used in the genetic engineered variant was not well suited to extreme drought. Maharashtra, Karnataka, and Tamil Nadu had an average 42% increase in yield with GM cotton in the same year. Drought resistant variants were developed and, with the substantially reduced losses to insect predation, by 2009 87% of Indian cotton was GM. [ Though disputed the economic and environmental benefits of GM cotton in India to the individual farmer have been documented.

Slide 11:

In 2009, countries that grew 95% of the global transgenic crops were the United States (46%), Brazil (16%), Argentina (15%), India (6%), Canada (6%), China (3%), Paraguay (2%) and South Africa (2%). The Grocery Manufacturers of America estimate that 75% of all processed foods in the U.S. contain a GM ingredient. In particular, Bt corn, which produces the pesticide within the plant itself, is widely grown, as are soybeans genetically designed to tolerate glyphosate herbicides. These constitute "input-traits" are aimed to financially benefit the producers, have indirect environmental benefits and marginal cost benefits to consumers. In the US, by 2009/2010, 93% of the planted area of soybeans, 93% of cotton, 86% of corn and 95% of the sugar beet were genetically modified varieties. Genetically modified soybeans carried herbicide-tolerant traits only, but maize and cotton carried both herbicide tolerance and insect protection traits (the latter largely the Bacillus thuringiensis Bt insecticidal protein). In the period 2002 to 2006, there were significant increases in the area planted to Bt protected cotton and maize, and herbicide tolerant maize also increased in sown area.

Legal issues in the US :

Legal issues in the US Alfa Alfa On 21 June 2010, the US Supreme Court issued its first ruling in regard to a GM crop. This was a ruling in regard to Roundup Ready alfalfa. The case goes back to 2006, when organic farmers, concerned about the impact of GM alfalfa on their crops, sued Monsanto. In response, the California Northern District Court ruled that the United States Department of Agriculture (USDA) was in error when it approved the planting of Roundup Ready alfalfa. According to the presiding judge, the law required the USDA to first conduct a full environmental study, which it had not done. It was the concern of the organic growers that the GM alfalfa could cross-pollinate with their organic alfalfa, making their crops unsalable in countries that forbid the growing of GM crops. The impact of the current US Supreme Court ruling is somewhat unclear, with both sides appearing to claim victory. While Monsanto can claim technical victory in the case, various other issues still remain open, and will likely be litigated in the future. Meanwhile, the planting of GM alfalfa currently remains halted in the US, and it is unclear when it may resume.

Sugar beet:

Sugar beet Between 2009 and 2011, the United States District Court for the Northern District of California considered the case involving the planting of genetically modified sugar beets. This case involves Monsanto's breed of pesticide-resistant sugar beets. Earlier in 2010, Judge Jeffrey S. White allowed the planting of GM sugar beets to continue, but he also warned that this may be blocked in the future while an environmental review was taking place. Finally, on 13 August 2010, Judge White ordered a halt to the planting of the genetically modified sugar beets in the US. He indicated that "the Agriculture Department had not adequately assessed the environmental consequences before approving them for commercial cultivation." The decision was the result of a lawsuit organized by the Center for Food Safety, a US non-governmental organization that is a critic of biotech crops.

Slide 20:

Crop yield A 1999 study by Charles Benbrook, Chief Scientist of the Organic Center, found that genetically engineered Roundup Ready soybeans did not increase yields. The report reviewed over 8,200 university trials in 1998 and found that Roundup Ready soybeans had a yield drag of 5.3% across all varieties tested. In addition, the same study found that farmers used 2-5 times more herbicide (Roundup) on Roundup Ready soybeans compared to other popular weed management systems. However research published in Science in 2003 has shown that the use of genetically modified Bt cotton in India increased yields by 60% over the period 1998-2001 while the number of applications of insecticides against bollworm were three times less on average. A 2008 Soil Association report found that some scientific studies claimed that genetically modified varieties of plants do not produce higher crop yields than normal plants. In 2009 the Union of Concerned Scientists summarized numerous peer-reviewed studies on the yield contribution of genetic engineering in the United States. This report examined the two most widely grown engineered crops—soybeans and maize (corn). Unlike many other studies, this work separated the yield contribution of the engineered gene from that of the many naturally occurring yield genes in crops.

Slide 23:

The report found that engineered herbicide tolerant soy and maize did not increase yield at the national, aggregate level. Maize engineered with Bt insect resistance genes increased national yield by about 3 to 4 percent. Engineered crops increased net yield in all cases. The study concluded that in the United States, other agricultural methods have made a much greater contribution to national crop yield increases in recent years than genetic engineering. United States Department of Agriculture data record maize yield increases of about 28 percent since engineered varieties were first commercialized in the mid 1990s. The yield contribution of engineered genes has therefore been a modest fraction—about 14 percent—of the maize yield increase since the mid 1990s. A 2010 article summarised the results of 49 peer reviewed studies on GM crops worldwide. On average, farmers in developed countries experienced increase in yield of 6% and in underdeveloped countries of 29%. Tillage was decreased by 25-58% on herbicide resistant soybeans, insecticide applications on Bt crops were reduced by 14-76% and 72% of farmers worldwide experienced positive economic results.