Question : One of the main objective of biotechnology is to minim.ise the use of insecticides on cultivated crops. Explain with the help of a suitable example how insect resistant crops have been developed using techniques of biotechnology.

Question : One of the main objective of biotechnology is to minim.ise

1.	Question : One of the main objective of biotechnology is to minim.ise the use of insecticides on cultivated crops. Explain with the help of a suitable example how insect resistant crops have been developed using techniques of biotechnology.
Answer» Solution : By using the techniques of biotechnology, Insect RESISTANT crops have been developed. Some strain of Bacillus thuringiensis (Bt) produce protein crystals which contain a toxic insecticidal protein that kill some insects like lepidopterans, coleopterans and DIPTERANS, etc. Specific Bt toxin genes were isolated from Bacillus thuringiensis and CLONED in bacteria. Specific_ Bt toxin genes obatained from Bacillus thuringiensis are used in several crop plants like cotton by providing them resistance from insects. Bt toxins arinsect-group specific, coded by a GENE called cry which are of various types. PROTEINS encoded by the genes cry IAc and cry IIAb control the cotton boll worms, that of cryIAb controls corn borer.