EMASCULATION MEANING- PURPOSE & METHODS
DEFINITION
It is the process of removal of stamens or anthers or killing of pollen grains of a flower without affecting the female reproductive organs. Simply it means removal of masculinity.
Emasculation is used during process of hybridization for crop improvement programme.
PURPOSE OF EMASCULATION
Emasculation is essential process in bisexual flowers to obtain the desired variety of a plant by crossing a particular plant with the desired pollen grain.
- The main objective is to prevent self-fertilization in the flowers.
- In monoecious plants, male flower or male inflorescence (maize) are removed; while in the case of dioecious plants, male plants are removed.
Process
To remove the anthers, the flowers are covered with a bag before they open. This ensures that the flower is pollinated by pollen grains obtained from desirable varieties only. Later, the mature, viable, and stored pollen grains are dusted on the bagged stigma by breeders to allow artificial pollination to take place and obtain the desired plant variety.
Selfing and crossing are essential in crop breeding programme. Breeders manipulate the pollination according to his needs in order to improve or introduce new traits.
METHODS OF EMASCULATION
- Hand Emasculation- In the species with large flowers, forceps are used to remove the anthers. The process is done one day before the anthers are expected to dehisce or mature and the stigma is likely to become mature. The fair time is 4-6 p.m. in the evening.
- Suction Method- This technique is useful in the species with small flowers. Emasculation is done in the morning just before or immediately after opening of flowers. In this method, suction hose is used to suck the anthers from flowers.
- Hot water treatment- Such treatment is given before anthers mature and before opening of flowers. The time as well as duration of treatment varies from crop to crop. For example, in jowar, treatment of flower with water at 42-48°C for 10 minutes and 10 minutes treatment with water at 40-44°C in rice kill the pollen grains.
- Alcohol treatment- In this method, inflorescence is immersed in suitable concentration of alcohol for short period of time. For example, in sweet clover, immersion of the inflorescence in 57% alcohol for 10 seconds was highly effective. It’s not a common method.
- Cold treatment- This method is also based on temperature of water and treatment period depends on the degree to kill the pollen grains without affecting gynoecium. In rice, cold water treatment at 0-6°C kills the pollen grains. Similarly, exposure of wheat plant at 0-2°C for 15-24 hours kills the pollen grains.
- Genetic emasculation- Here genetic or cytoplasmic male sterility may be used to avoid other techniques of emasculation. This method is used in commercial production of maize, pearl millet, cotton, rice etc.
Read more..
WHAT IS POLLINATION- PROCESS & MECHANISM
SELF POLLINATION- MECHANISM & CONSEQUENCES
CROSS POLLINATION- MECHANISM AND CONSEQUENCES
WHAT IS HYBRIDIZATION-FACTS ,AIM & TYPES
REPRODUCTION IN PLANTS