Q.Give an account of mutation breeding with examples.

Step 1. Define mutation and mutation breeding. Mutation is a sudden, heritable change in an organism's genotype, occurring naturally or induced deliberately by chemicals or physical agents. Mutation breeding is the deliberate use of such induced mutations as raw material for creating new, improved crop varieties.

Step 2. Name the mutagens used. Natural (physical) mutagens include high temperature, elevated carbon dioxide concentration, X-rays and UV rays. Chemical mutagens include nitrous acid, EMS (ethyl methyl sulphonate), mustard gas and colchicine.

Step 3. Describe the process. Seedlings or seeds are irradiated — for instance with cobalt-60 — or exposed to UV lamps or X-ray machines; these mutagens cause gene mutations and chromosomal aberrations. The treated seedlings are then screened, exactly as in ordinary breeding, for useful traits such as disease resistance, pest resistance and higher yield, and only the genuinely improved, stable mutant lines are selected and multiplied. …

Defining mutation breeding, listing its physical/chemical mutagens, describing the induce-and-screen proc …

• Confusing mutation breeding (starting from a randomly induced genetic change in one variety) with hybridization (combining traits already present in two different parent varieties). …