Question

Bt cotton genes repel
A. Bacterial pathogens
B. Fungal pathogens
C. Nematode parasites
D. Insect pests

Answer 1

Bt cotton is a type of plant cotton that is immune to genetically modified organisms (GMO) or genetically modified pests, providing an insecticide for bollworm control.

Complete Answer:
- GM crops (mainly cotton and maize), resistant to plague, have been genetically engineered to be poisonous to some insects. They are also called Bt crops because in a bacterial species called Bacillus thuringiensis, the introduced genes were originally identified. A group of toxins called Cry toxins are produced by these bacteria.
- Over 200 different Bt toxins are produced by strains of the Bacillus thuringiensis bacterium, each harmful to various insects. In particular, Bt toxins are insecticidal to moth and butterfly larvae, beetles, cotton bollworms and flies, but are harmless to other life forms. The Bt toxin coding gene has been incorporated as a transgene into cotton, causing it to develop this natural insecticide in its tissues.
- In several countries, lepidopteran larvae that are destroyed by the Bt protein in the genetically modified cotton they consume are the main pests of commercial cotton. This removes the need for vast quantities of broad-spectrum insecticides (some of which have developed pyrethroid resistance) to be used to destroy lepidopteran pests.
- In the farm area, this saves natural insect predators and also leads to the control of non-insecticide pests.Bt cotton is ineffective against many cotton pests such as plant bugs, stink bugs, and aphids; it may be beneficial to use insecticides for prevention depending on the circumstances.

The correct Answer is option (D) Insect pests.

Note: There are some benefits of Bt cotton over non-Bt cotton. Briefly, the major advantages of Bt cotton:
1. Reduction of the use of insecticides in Bt cotton production, in which bollworms are major pests.
2. Potential decrease in cultivation costs (depending on the cost of the seed versus the cost of insecticides).