Specific cry genes are selected depending upon crop and targeted pest. Cotton bollworms are controlled by:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → cryIAc and cryIIAb
Bt toxin is a protein made by the bacterium Bacillus thuringiensis. It is coded by cry genes. Each cry gene gives a toxin that kills one group of insects, so the gene is chosen to suit the crop and the pest.
(1) cryIAb — Incorrect. This gene controls the corn borer, not the cotton bollworm.
(2) cryIAb and cryIIAb — Incorrect. cryIIAb is right for the cotton bollworm, but cryIAb belongs to the corn borer.
(3) cryIAc and cryIIAb — Correct. Together these two genes make toxins that control the cotton bollworms.
(4) cryIAc — Incorrect. It is only one of the two genes. cryIIAb is also needed.
NCERT Extract:
Biotechnological Applications in Agriculture – …
