How to Control Pollination Through Emasculation Tagging and Bagging?
Aim: To control pollination through emasculation, tagging, and bagging.
Materials Required:
Plants with large bisexual flowers
Tweezers
Scissors
Brush
Alcohol
Rubber bands
Paper bags
Paper clips
Tags
Magnifying Glass
Theory
Emasculation is defined as the process of artificial hybridization in which female flowers' stamens are separated from bisexual flowers in order to avoid self-fertilization. Much before the anthers mature, this process takes place. Emasculation is the method of extracting anthers from bisexual flowers before they mature. After that, the emasculated flower is bagged to keep any unwanted pollination.
This method aids in the development of flowers that have the desired characteristics. It is essential to have knowledge of flower structure, fertilization, flower physiology, and fertilization for this.
Procedure to Controlled Pollination Emasculation Tagging and Bagging:
Choose a flower bud and open it to extract the stamens. This is referred to as emasculation. It is the female parent vine, so make a note of it.
The plant is then wrapped in a plastic bag to keep unwanted pollen from pollinating it.
Bring it in contact with the anther of a male plant that has the desired traits. The pollen should be dusted on the stigma's surface.
Cover the pollinated flower with a polythene bag and mark it with the seed parent's name as soon as possible.
Pollination
Pollination is a plant reproduction process in which pollen grains are transferred from the anther to the stigma. There are two forms of pollination:
Cross-pollination
Self-pollination
Pollen and stigma must be compatible for pollination to be effective. Pollen grains can be rejected due to incompatibility. This is unfavorable, especially in commercial crop production. Artificial hybridization was established as a result.
Artificial Hybridization
For successful pollination and fertilization, pollen-stigma compatibility is important. When compatible pollen is accepted by the pistil, fertilization events begin, while incompatible pollen is rejected. The ability of a pistil to recognize its pollen is the product of long-term pollen-pistil interaction as well as chemicals released by pollen.
Steps in Artificial Hybridization
Hybridization proceeds in two steps:
Emasculation
Bagging
Emasculation
Hybridization is a form of selective breeding, as we all know. Anthers must be removed from a bisexual flower before pollen grains can be released. Emasculation is the process of removing an Anther with forceps. This phase is not expected in the case of unisexual flowers.
Bagging
Bagging is an essential component of all pollination operations. Until anthesis, the female (receptive) flowers must be protected to protect the stigma from contamination before the desired pollen can be added. Usually, the bag is made of semi-transparent treated paper. By securing the bag over the shoot's tip, the flowers can be secured. To make the bags more comfortable, they must be tightly fitted and fixed.
Bagging is a way of shielding emasculated flowers from unwanted pollen grains. Despite the fact that the flower is obscured by a bag, it achieves receptivity. Bagging is performed before the flowers open in unisexual flowers.
The female flower is absolutely covered from contamination thanks to emasculation and bagging.
The desired pollen is dusted on the stigma once the flower has achieved stigma receptivity. This has been resealed in preparation for future developments.
As a result, artificial hybridization ensures that the correct form of pollen is transferred to the flower's stigma. Furthermore, there is a fair possibility of fertilization. This method allows for the production of a wide range of crop strains while also improving the quality of crops with desirable characters.
Emasculation & Bagging Techniques to Achieve Artificial Hybridization
Emasculation – Emasculation is the process of artificial hybridization where the pollen and anthers of the flower are separated to prevent self-pollination.
Bagging – Bagging involves covering the emasculated flower with a bag to prevent pollinating agents from reaching it.
The stigma of emasculated flowers can be dusted with pollen of the desired kind.
Artificial hybridization is therefore possible.
Control Pollination
Control-pollination is a plant enhancement technique that produces progeny with genes from each of two established parent plants. Transferring pollen from one plant to the receptive female reproductive organs of another plant while removing all other pollen is known as control pollination.
Control-pollination is necessary to:
To establish and maintain a pedigreed breeding population, control pollination is required.
In order to control inbreeding in the breeding population
Hybridization and back-cross between species must be done.
Control-pollination techniques are specifically engineered and managed to generate seeds with greater genetic trait and genetic uniformity than naturally pollinated seeds, as well as eliminating pollen contamination issues.
Importance of Pollination
Pollination in plants can happen in two ways, self-pollination that happens within the same plant and cross-pollination that happens across the plants. Insects, water, wind etc, which facilitates pollination in plants are known as pollinating agents. However, insects were the first pollinating agents that helped the plants from their primitive stages. Pollination in plants plays a key role in the sexual reproduction of plants. It benefits not only plants but also human beings and animals by providing various fruits that we eat and flowers we use to decorate. Even today, many tribals who live in forests have fruits as their main source of nutrition. Artificial hybridization techniques have improved these chances of utilizing the plants much better. The flowers produced through pollination are a key source in the perfume industry and horticulture industry. Flowers play an important role also in the soap manufacturing and talcum powder industries. With the rise of industries and machines, humans can now process these natural gifts and store them for a longer period.
FAQs on Controlled Pollination Emasculation Tagging and Bagging
1. What are emasculation and bagging in the context of plant breeding?
These are two key techniques used in artificial hybridization for crop improvement.
- Emasculation is the process of removing the anthers or stamens from a bisexual flower before they mature and release pollen. This is done to prevent self-pollination.
- Bagging is the process of covering the emasculated flower with a bag, typically made of butter paper, to prevent contamination from any unwanted foreign pollen.
2. What is the step-by-step process for controlled pollination using these techniques?
The process of artificial hybridization involves several precise steps to ensure the creation of a plant with desired traits:
- Parent Selection: Choose parent plants with the desired characteristics.
- Emasculation: Carefully remove the anthers from the selected female parent's bisexual flower before the flower bud opens.
- Bagging: Immediately cover the emasculated flower with a bag to prevent any stray pollen from landing on the stigma.
- Pollen Collection: Collect mature pollen grains from the desired male parent plant.
- Pollination: Once the stigma of the bagged female flower becomes receptive, dust the collected pollen onto it.
- Re-bagging and Tagging: The flower is bagged again and a tag is attached with details like the date of pollination and the parent plants used.
3. Why is it crucial to perform emasculation before the flower bud opens (anthesis)?
Performing emasculation before anthesis is critical to prevent self-pollination. If the flower bud opens, its own anthers may mature and dehisce (burst), releasing pollen onto the stigma. This would lead to self-fertilisation, defeating the entire purpose of artificial hybridization, which aims to cross-breed with pollen from a different, specifically chosen plant to introduce desired genetic traits.
4. What is the importance of tagging in a controlled pollination experiment?
Tagging is essential for maintaining accurate records in plant breeding programs. The tag attached to a pollinated flower contains vital information such as:
- The date of emasculation.
- The date of pollination.
- Details of the male parent (pollen source) and female parent.
5. How does the process of artificial hybridization differ for unisexual flowers?
The process is simpler for unisexual flowers. Since a female flower (pistillate) naturally lacks stamens, there is no need for emasculation. However, bagging is still a necessary step. The female flower bud must be bagged before it opens to prevent pollination by any random, undesirable pollen. Once the stigma is receptive, controlled pollination with desired pollen is carried out, followed by re-bagging.
6. What are the primary objectives of using controlled pollination in crop improvement programs?
The main goal of controlled pollination, or artificial hybridization, is to combine desirable characters from two different parent plants into a single offspring. The key objectives include:
- Creating new varieties with higher yield, better quality, or increased resistance to diseases and pests.
- Ensuring that only the desired pollen grains are used for fertilisation, leading to greater genetic uniformity.
- Overcoming issues of pollen-pistil incompatibility that might prevent natural fertilisation in commercial crops.
- Controlling inbreeding within a breeding population to maintain genetic diversity.
7. If a flower is sealed in a bag, how does it survive and remain receptive for pollination?
The bags used in this technique are specifically designed to allow the flower to survive. They are typically made of a semi-transparent material like butter paper which has minute pores. These pores prevent larger particles like pollen grains from entering but are large enough to permit gaseous exchange. This allows the flower to respire and photosynthesise, keeping it healthy and viable until the stigma becomes receptive for artificial pollination.
