Breeding of Fruit and Plantation Crops 2 + 1

Mutagenesis

• Treating a biological material with a mutagen in order to induce mutations is known as mutagenesis.
• Agents which induce mutations are known as mutagens. Mutagens may be different kinds of radiation (physical mutagens) or certain chemicals (chemical mutagens).

a.Physical mutagens

1. Ionising radiation:
2. Particulate radiation e.g., α- rays, β-rays, fast neutrons and thermal neutrons
3. Nonparticulate radiation (Electromagnetic radiation) – X- rays and γ- rays
4. Nonionising radiation : ultraviolet radiation

b.Chemical mutagens

1. Alkylating agents : EMS- ethylmethane sulphonate, MMS- methyl methane sulphonate
2. Acridine dyes : acridine orange, acridine yellow, ethidium bromide
3. Base analogues : 5- bromouracil, 5-chlorouracil
4. Others: nitrous acid, hydroxyl amine, sodium azide.