Editing Cotton (section)

=== Genetic modification ===
{{Main|Bt cotton}}
[[Genetic engineering|Genetically modified]] (GM) cotton was developed to reduce the heavy reliance on pesticides. The bacterium ''[[Bacillus thuringiensis]]'' (Bt) naturally produces a chemical harmful only to a small fraction of insects, most notably the larvae of [[Lepidoptera|moths and butterflies]], [[Coleoptera|beetles]], and [[Diptera|flies]], and harmless to other forms of life.<ref>{{Cite journal|title = Are Bt crops safe?|journal = Nature Biotechnology|date = 2003-01-01|volume = 21|issue = 9|doi = 10.1038/nbt0903-1003|first1 = Mike|last1 = Mendelsohn|first2 = John|last2 = Kough|first3 = Zigfridais|last3 = Vaituzis|first4 = Keith|last4 = Matthews|pmid=12949561|pages=1003–9|s2cid = 16392889|url = https://zenodo.org/record/1233343}}</ref><ref>{{cite journal |last1=Hellmich |first1=Richard L. |last2=Siegfried |first2=Blair D. |last3=Sears |first3=Mark K. |last4=Stanley-Horn |first4=Diane E. |last5=Daniels |first5=Michael J. |last6=Mattila |first6=Heather R. |last7=Spencer |first7=Terrence |last8=Bidne |first8=Keith G. |last9=Lewis |first9=Leslie C. |title=Monarch larvae sensitivity to Bacillus thuringiensis- purified proteins and pollen |journal=Proceedings of the National Academy of Sciences of the United States of America |date=9 October 2001 |volume=98 |issue=21 |pages=11925–11930 |doi=10.1073/pnas.211297698 |pmid=11559841 |pmc=59744 |bibcode=2001PNAS...9811925H |doi-access=free }}</ref><ref>{{cite journal |last1=Rose |first1=Robyn |last2=Dively |first2=Galen P. |last3=Pettis |first3=Jeff |title=Effects of Bt corn pollen on honey bees: emphasis on protocol development |journal=Apidologie |date=July 2007 |volume=38 |issue=4 |pages=368–377 |doi=10.1051/apido:2007022 |s2cid=18256663 |url=https://www.apidologie.org/10.1051/apido:2007022/pdf }}</ref> The gene coding for Bt toxin has been inserted into cotton, causing cotton, called [[Bt cotton]], to produce this natural insecticide in its tissues. In many regions, the main pests in commercial cotton are [[lepidoptera]]n larvae, which are killed by the Bt protein in the transgenic cotton they eat. This eliminates the need to use large amounts of broad-spectrum insecticides to kill lepidopteran pests (some of which have developed [[pyrethroid]] resistance). This spares natural insect predators in the farm ecology and further contributes to noninsecticide pest management.

However, Bt cotton is ineffective against many cotton pests, such as [[plant bug]]s, [[Halyomorpha halys|stink bugs]], and [[aphid]]s; depending on circumstances it may still be desirable to use insecticides against these. A 2006 study done by Cornell researchers, the Center for Chinese Agricultural Policy and the Chinese Academy of Science on Bt cotton farming in China found that after seven years these secondary pests that were normally controlled by pesticide had increased, necessitating the use of pesticides at similar levels to non-Bt cotton and causing less profit for farmers because of the extra expense of GM seeds.<ref>{{cite web|publisher=Cornell University|date=25 July 2006|title=Seven-year glitch: Cornell warns that Chinese GM cotton farmers are losing money due to 'secondary' pests|author=Lang, Susan|url=http://www.news.cornell.edu/stories/July06/Bt.cotton.China.ssl.html|url-status=live|archive-url=https://web.archive.org/web/20121012044920/http://www.news.cornell.edu/stories/July06/Bt.cotton.China.ssl.html|archive-date=12 October 2012}}</ref> However, a 2009 study by the Chinese Academy of Sciences, Stanford University and Rutgers University refuted this.<ref>{{Cite journal | last1 = Wang | first1 = Z. | last2 = Lin | first2 = H. | last3 = Huang | first3 = J. | last4 = Hu | first4 = R. | last5 = Rozelle | first5 = S. | last6 = Pray | first6 = C. | doi = 10.1016/S1671-2927(09)60012-2 | title = Bt Cotton in China: Are Secondary Insect Infestations Offsetting the Benefits in Farmer Fields? | journal = Agricultural Sciences in China | volume = 8 | pages = 83–90 | year = 2009 }}</ref> They concluded that the GM cotton effectively controlled bollworm. The secondary pests were mostly miridae (plant bugs) whose increase was related to local temperature and rainfall and only continued to increase in half the villages studied. Moreover, the increase in insecticide use for the control of these secondary insects was far smaller than the reduction in total insecticide use due to Bt cotton adoption. A 2012 Chinese study concluded that Bt cotton halved the use of pesticides and doubled the level of ladybirds, lacewings and spiders.<ref name=20120613Guardian>Carrington, Damien (13 June 2012) [https://www.theguardian.com/environment/2012/jun/13/gm-crops-environment-study?INTCMP=SRCH GM crops good for environment, study finds] {{webarchive|url=https://web.archive.org/web/20131005002523/http://www.theguardian.com/environment/2012/jun/13/gm-crops-environment-study?INTCMP=SRCH |date=5 October 2013 }} The Guardian, Retrieved 16 June 2012</ref><ref>{{cite journal| last1 = Lu y | first1 = W. K.| last2 = Wu | first2 = K.| last3 = Jiang | first3 = Y.| last4 = Guo | first4 = Y.| last5 = Desneux | first5 = N.| title = Widespread adoption of Bt cotton and insecticide decrease promotes biocontrol services| journal = Nature| volume = 487| issue = 7407| pages = 362–365| date=July 2012 | pmid = 22722864| doi = 10.1038/nature11153|bibcode = 2012Natur.487..362L | s2cid = 4415298}}</ref> The [[International Service for the Acquisition of Agri-biotech Applications]] (ISAAA) said that, worldwide, GM cotton was planted on an area of 25 million hectares in 2011.<ref name = ISAAA/> This was 69% of the worldwide total area planted in cotton.

GM cotton acreage in India grew at a rapid rate, increasing from 50,000 hectares in 2002 to 10.6 million hectares in 2011. The total cotton area in India was 12.1 million hectares in 2011, so GM cotton was grown on 88% of the cotton area. This made India the country with the largest area of GM cotton in the world.<ref name=ISAAA>[http://www.isaaa.org/resources/publications/briefs/43/executivesummary/default.asp ISAAA Brief 43-2011: Executive Summary Global Status of Commercialized Biotech/GM Crops: 2011] {{webarchive|url=https://web.archive.org/web/20120210025832/http://www.isaaa.org/resources/publications/briefs/43/executivesummary/default.asp |date=10 February 2012 }}. Retrieved 24 September 2012.</ref> A long-term study on the economic impacts of Bt cotton in India, published in the Journal [[PNAS]] in 2012, showed that Bt cotton has increased yields, profits, and living standards of [[smallholding|smallholder]] farmers.<ref>{{cite journal|doi=10.1073/pnas.1203647109|title=Economic impacts and impact dynamics of Bt (''Bacillus thuringiensis'') cotton in India|year=2012|last1=Kathage|first1=J.|last2=Qaim|first2=M.|journal=Proceedings of the National Academy of Sciences|volume=109|issue=29|pages=11652–6|pmid=22753493|pmc=3406847|bibcode=2012PNAS..10911652K|doi-access=free}}</ref> The U.S. GM cotton crop was 4.0 million hectares in 2011 the second largest area in the world, the Chinese GM cotton crop was third largest by area with 3.9 million hectares and Pakistan had the fourth largest GM cotton crop area of 2.6 million hectares in 2011.<ref name = ISAAA/> The initial introduction of GM cotton proved to be a success in Australia&nbsp;– the yields were equivalent to the non-transgenic varieties and the crop used much less pesticide to produce (85% reduction).<ref>[https://web.archive.org/web/20120419154729/http://www.cottonaustralia.com.au/facts/factsandfigures.aspx?id=14 Facts & Figures/Natural Resource Management Issues], Biotechnology, 2010. cottonaustralia.com.au.</ref> The subsequent introduction of a second variety of GM cotton led to increases in GM cotton production until 95% of the Australian cotton crop was GM in 2009<ref name=GMOCompass>[http://www.gmo-compass.org/eng/agri_biotechnology/gmo_planting/343.genetically_modified_cotton_global_area_under_cultivation.html Genetically modified plants: Global Cultivation Area Cotton] {{webarchive|url=https://web.archive.org/web/20100729093637/http://www.gmo-compass.org/eng/agri_biotechnology/gmo_planting/343.genetically_modified_cotton_global_area_under_cultivation.html |date=29 July 2010 }} GMO Compass, 29 March 2010. Retrieved 7 August 2010.</ref> making Australia the country with the fifth largest GM cotton crop in the world.<ref name = ISAAA/> Other GM cotton growing countries in 2011 were Argentina, Myanmar, Burkina Faso, Brazil, Mexico, Colombia, South Africa and Costa Rica.<ref name = ISAAA/>

Cotton has been genetically modified for resistance to [[glyphosate]] a broad-spectrum herbicide discovered by Monsanto which also sells some of the Bt cotton seeds to farmers. There are also a number of other cotton seed companies selling GM cotton around the world. About 62% of the GM cotton grown from 1996 to 2011 was insect resistant, 24% [[Gene stacked event|stacked]] product and 14% herbicide resistant.<ref name = ISAAA/>

Cotton has [[gossypol]], a toxin that makes it inedible. However, scientists have silenced the gene that produces the toxin, making it a potential food crop.<ref>Bourzac, Katherine (21 November 2006) [http://www.technologyreview.com/Biotech/17812/ Edible Cotton]. ''MIT Technology Review''.</ref> On 17 October 2018, the [[USDA]] deregulated [[Genetic Engineering|GE]] low-gossypol cotton.<ref>{{cite web |url=https://www.aphis.usda.gov/aphis/ourfocus/biotechnology/brs-news-and-information/2018_brs_news/texas_am_low_gossypol_cotton |title=USDA Announces Deregulation of GE Low-Gossypol Cotton |publisher=United States Department of Agriculture |format=website |access-date=21 October 2018 |archive-date=22 October 2018 |archive-url=https://web.archive.org/web/20181022033541/https://www.aphis.usda.gov/aphis/ourfocus/biotechnology/brs-news-and-information/2018_brs_news/texas_am_low_gossypol_cotton |url-status=dead }}</ref><ref>{{cite web |url=https://www.aphis.usda.gov/brs/fedregister/BRS_20181017.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.aphis.usda.gov/brs/fedregister/BRS_20181017.pdf |archive-date=2022-10-09 |url-status=live |title=Federal Register: Texas A&M AgriLife Research; Determination of Nonregulated Status of Cotton Genetically Engineered for Ultra-low Gossypol Levels in the Cottonseed  |publisher=National Archives and Records Administration  |access-date=21 October 2018}}</ref>