- Bt cotton is genetically modified cotton crop that expresses an insecticidal protein whose gene has been derived from a soil bacterium called Bacillus thuringiensis, commonly referred as Bt.
Which insects does it control?
- In 1996, Bollgard cotton ( a trade mark of Monsanto) was the first Bt cotton to be marketed in the U.S.
- The Bollgard cotton produce a toxin called Cry 1Ac that has excellent activity on tobacco budworm and pink bollworm.
- These two insects are extremely important caterpillar pests of cotton and both are difficult to and expensive to control with traditional insecticides.
- Bollgard II was introduced in 2003, representing the next generation Bt cotton.
- Bollgard II contains a second gene from the Bt bacteria, which encodes the production of Cry 2Ab.
- Bollgard II has a better activity on wide range of caterpillar pests.
Advantages of Bt Cotton:
Bt cotton has several advantages over non-Bt cotton. Some of them are:
- Increases yield of cotton due to effective control of bollworms.
- Reduction in use of insecticide.
- Reduction in the cost of cultivation (depending on seed cost versus insecticide costs).
- Reduction in environmental pollution by the use of insecticides.
- Bt cotton is eco-friendly and does not have adverse effect on parasites, predators, beneficial insecticides and organisms present in soil.
- It promotes multiplication of parasites and predators which help in controlling the bollworms by feeding on larvae and eggs of bollworm.
Disadvantages of Bt Cotton:
- Bt cotton seeds are costly than non Bt cotton seeds.
- The toxin producing efficiency of the Bt gene reduces after 120 days.
- Ineffective against sucking pests like jassids, aphids, whitefly etc.
Introduction in India:
- In India all the transgenic crops require environmental clearance under the Environment (Protection) Act, 1986
- In 2002, Bt Cotton was granted approval and it became the first GM crop approved in India.
- Mahyco became the first Indian company to commercialise transgenic cotton hybrids in India in 2002.
- The commercial cultivation in Bt cotton was launched in Six States:- Andhra Pradesh,Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Tamil Nadu.
Some Issues related to Bt Cotton in India:
- Farmers suicides in some cotton growing states.
- Indiscriminate use of Bt hybrids instead of Bt straight.
- Late maturing Bt hybrids are not suitable for rain fed conditions.
- Health implications raised by Bt cotton.
- Contamination of indigenous crops.
- Environmental concerns and bio-safety issues.
- Reduction in average yield of cotton over the years.