Breeding of Fruit and Plantation Crops 2 + 1

General characteristics of mutation

• Mutations are generally recessive but dominant mutations also occur.
• Mutations are generally harmful to the organism.
• Mutations are random.
• Mutations are recurrent.
• Induced mutations commonly show pleiotrophy, often due to mutations in closely linked gene.

Mutagens

• Agents used for induction of mutations, are known as mutagens. The different mutagens may be grouped as follows:

Physical mutagens

• Ionizing radiations
• Particulate radiations – α-rays, fast neutron, thermal neutrons.
• Non-particulate radiations – X-rays, γ-rays.
• Non ionizing radiation – Ultraviolet radiation.

Chemical mutagens

• Alkylating agents – Sulphur mustard, mustard gas, EMS (Ethyl methane sulphonate), Ethylene Imine (EI)
• Acridine dyes- acriflavin, proflavin, acridine orange, acridine yellow,ethedium bromide.
• Base analogues – 5-bromouracil, 5-Chlorouracil.
• Others – Nitric acid, hydroxyl amine.

Achievements

• Mango – Rosica from Peruvian variety Rosadodelca
• Papaya- Pusa Nanha from local type
• Grape-Marvel Seedless from Delight
• Banana- High gate from Gros Michel, Motta Poovan from Poovan
• Orange-Washington Navel
• Grapefruits – Marsh and Thompson