Bt cotton
Bt cotton is a genetically modified (GM) variety of cotton [https://utcrops.com/cotton/insects-and-mites/biological-control/bt-cotton/][https://en.wikipedia.org/wiki/Bt_cotton][https://researchoutreach.org/articles/genetically-modified-cotton-how-changed-india/] that incorporates one or more genes from the soil bacterium Bacillus thuringiensis (Bt) [https://utcrops.com/cotton/insects-and-mites/biological-control/bt-cotton/]. These genes produce insecticidal proteins, creating a plant that naturally produces toxins to combat insect pests [https://utcrops.com/cotton/insects-and-mites/biological-control/bt-cotton/]. Specifically, it’s designed to combat bollworms, a major cotton pest [https://en.wikipedia.org/wiki/Bt_cotton].
How it works: The Bt genes encode for Cry toxins and/or Vip toxins, targeting specific caterpillar pests like bollworms [https://ejbpc.springeropen.com/articles/10.1186/s41938-018-0051-2]. When bollworms consume the Bt cotton leaves, the toxins become active in their digestive systems, leading to paralysis and death [https://byjus.com/biology/bt-crops/]. This reduces the need for chemical insecticides, although the extent of this reduction and its long-term sustainability are debated [https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1102395/full].
Development and Adoption: Bt cotton was first introduced in India almost twenty years ago [https://researchoutreach.org/articles/genetically-modified-cotton-how-changed-india/], and its adoption has been widespread in many cotton-producing countries [https://jcottonres.biomedcentral.com/articles/10.1186/s42397-024-00192-z]. However, there are concerns about its effectiveness and sustainability, with some studies suggesting that its yield gains have plateaued and its pest resistance is declining [https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1102395/full][https://www.iatp.org/sites/default/files/What_Is_Wrong_With_Bt_Cotton.htm]. The development of herbicide-tolerant Bt (HT-Bt) hybrid cottons is ongoing, with some illegal planting already occurring in India [https://enveurope.springeropen.com/articles/10.1186/s12302-023-00804-6].
History: The bacterium Bacillus thuringiensis (Bt), the source of the insecticidal genes, was first isolated in 1901 by Japanese biologist Shigetane Ishiwatari [http://www.bt.ucsd.edu/bt_history.html]. The development and application of Bt technology in agriculture, including cotton, has followed since.
In summary: Bt cotton offers a genetically modified approach to pest control in cotton production, but its long-term efficacy and overall impact remain subjects of ongoing research and debate. The advantages and disadvantages need to be carefully considered in the context of specific agricultural practices and environmental conditions.
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