Most flowers contain both male and female parts.
The male parts, stamens, bear anthers that produce the male sex cells or pollen grains. The female part consists of the ovary which produces the female sex cells or ovules.
A seed is a fertilized ovule, that is formed as a result of the union between the male and female gametes, in a process called fertilization.
Fertilization is the fusion of male and female nuclei to form a zygote, which develops by cell division into an embryo. The seed is then formed from this embryo.
A seed is, therefore, a product of sexual reproduction in plants.
Using the sexual propagation method, seeds are used as planting materials.
Seeds may be planted directly into the field (in situ) or raised in the nursery before transplanting them into the field.
Examples of seeds planted in situ are maize, cowpea, okra, etc.
Examples of seeds nursed before transplanting are tomato, pepper, cocoa, etc.
Advantages of Sexual Propagation:
1. It’s a cheap way of growing a large number of plants.
2. Seeds when well stored can remain viable for a long time.
3. This method requires simple equipment and fewer facilities, than other methods of propagation.
4. Self-pollination gives rise to offspring which are like the parents.
5. Seeds are usually small, and convenient to handle, store, transport, procure and sow.
Disadvantages of Sexual Propagation:
1. Some seedlings raised from seeds are not pure.
2. Plants grown from seeds take a longer time to produce fruits.
3. It reduces the amount available for consumption.
4. Some plants don’t produce seeds, such as most varieties of bananas.
5. The plants could mature at different times and show variation in growth. This means that crops would be ready to sell at different times, which might be an issue for the farmer.
6. Seed germination may be poor.