Plant Reproduction
Primary 6 · Science and Elementary Technology
Plant Reproduction
Lesson 4 of 5
30 min
Let's begin
Before the rainy season, Mutesi helps her mother choose strong, healthy cassava stems. They cut them into pieces about as long as a school ruler and push them into the soil at a slant. Three weeks later, green shoots appear from the little bumps on each piece. No flower, no pollen, no seed, yet there are new cassava plants!
This is asexual reproduction. Farmers call it vegetative propagation, because they grow new plants from the leaves, stems or roots (the vegetative parts) of one parent.
A cutting is a piece of stem with several buds (the small bumps, also called nodes). Planted in moist soil, it grows new roots and shoots from the buds.
Always choose healthy, disease-free stems. The new plants are copies of the parent, so a sick parent gives sick plants.
A banana plant has an underground stem. Young shoots called suckers grow up from it, right beside the parent plant. The farmer digs up a strong sucker with some of its roots and plants it in a new hole. Pineapples can also be grown from suckers.
An Irish potato is a stem tuber: a swollen underground stem full of stored food. Its "eyes" are buds. Plant a small potato (or a piece with eyes), and each eye can sprout into a new plant.
An onion or a garlic clove is a bulb: a very short stem surrounded by thick, fleshy leaves full of food. Planted, it grows roots at the bottom and leaves at the top.
Ginger and some grasses have rhizomes, underground stems that grow sideways and send up new shoots along the way.
In grafting, a farmer joins a shoot (the scion) cut from a tree with excellent fruit onto a young rooted plant (the rootstock). The two are tied tightly together until they grow into one plant. Budding is the same idea, using just one bud. Avocado, mango and orange trees are often grafted, because a grafted tree bears fruit sooner, usually after about 3 years instead of many years from seed, and its fruit is the same as the tree the scion came from.
In layering, a low branch is bent down and part of it is covered with soil while it is still attached to the parent. It grows roots in the soil. Then it is cut from the parent and planted on its own.
| Method | Part used | Examples in Rwanda |
|---|---|---|
| Stem cuttings | Piece of stem with buds | Cassava, sugarcane, sweet potato vines |
| Suckers | Young shoots from an underground stem | Banana, pineapple |
| Tubers | Swollen underground stem with eyes | Irish potato |
| Bulbs | Short stem with fleshy leaves | Onion, garlic |
| Rhizomes | Sideways underground stem | Ginger |
| Grafting / budding | Shoot or bud joined to a rootstock | Avocado, mango, orange |
| Layering | Branch rooted while still attached | Some fruit bushes and flowers |
Tip
No flower, no seed, one parent. If a new plant grew from a stem, a sucker, a tuber, a bulb or a graft, it is asexual reproduction, and the new plant is a copy of its parent.
Answers
What you learned today
Sources and credits
The exercises (Try it yourself and the practice questions) are written by Ganzaa. The lesson text is written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
Quick check
Match each crop to the part farmers plant to grow it.
Tap one on the left, then its partner on the right.
