Mushrooms
Senior 2 · Agriculture
Mushrooms
Lesson 1 of 3
16 min
Let's begin
A mushroom farm needs no field. A single room with a few shelves, some maize cobs or straw that would otherwise be burnt, and a supply of "spawn" can produce fresh food within about six weeks. That is why many young people and women's cooperatives in Rwanda have taken up mushroom growing as a small business: little land, little capital, quick returns, and a crop that sells in markets, hotels and supermarkets.
Before you can grow mushrooms you need to understand what they are, because they live very differently from crops.
A mushroom is the fleshy, spore-producing fruiting body of a fungus. The main body of the fungus is hidden: a mass of fine white threads called hyphae, together forming the mycelium, which grows through soil, dead wood or straw. The mushroom that appears above the surface is only the part that makes and releases spores, much as an avocado is only one part of the tree. In Kinyarwanda mushrooms are called ibihumyo.
| Group | Examples | Notes |
|---|---|---|
| Cultivated edible | Oyster mushroom (Pleurotus), button mushroom (Agaricus bisporus), shiitake (Lentinula), wood ear (Auricularia) | Oyster mushrooms are the most widely grown in Rwanda: they grow fast on many cheap residues and tolerate warm rooms. |
| Wild edible | Species gathered after the rains in forests and grasslands | Only safe when collected by people who know the species very well. |
| Poisonous | Death cap (Amanita phalloides) and many others | Some are deadly. There is no simple test: colour, smell, peeling the cap or a silver spoon cannot tell you if a mushroom is safe. |
| Medicinal | Reishi (Ganoderma), shiitake | Used in traditional medicine and studied by scientists. |
Food value: mushrooms are low in fat and supply protein, fibre, B vitamins and minerals, which makes them a useful addition to diets based on starchy staples.
Question: Keza says, "Mushrooms grow in the soil and do not move, so they are plants." Use three features to show she is wrong.
Answer: (1) Mushrooms have no chlorophyll and cannot make their own food; they absorb food digested from dead matter. (2) Their cell walls contain chitin, while plant cell walls contain cellulose. (3) They reproduce by spores formed on gills, not by seeds from flowers. Mushrooms therefore belong to Kingdom Fungi.
Tip
Memory hook: "Mycelium is the tree, the mushroom is the fruit, spawn is the seed."
Exam technique: when asked about propagation, distinguish clearly between spores (natural, microscopic, used in the laboratory) and spawn (mycelium on grain, what the farmer buys and plants).
Define a mushroom.
Solution: A mushroom is the fleshy, spore-producing fruiting body of a fungus.
On which part of a mushroom are spores produced?
Solution: On the gills (lamellae) under the cap.
Why do mushroom growers use spawn instead of spores?
Solution: Spores are microscopic, easily contaminated and give variable offspring, so they need laboratory conditions. Spawn is actively growing, pure mycelium on grain that establishes quickly in the substrate and gives a predictable crop.
A neighbour says you can tell a poisonous wild mushroom because it turns a silver spoon black. How should you respond?
Solution: This is a myth. No simple test separates edible from poisonous mushrooms; some deadly species look and smell ordinary. Eat only cultivated mushrooms or wild species identified by a real expert.
Give two reasons why oyster mushrooms suit small-scale growers in Rwanda.
Solution: Any two: they grow on cheap, locally available residues such as maize cobs and straw; they need little space and no farmland; they tolerate the warm temperatures of ordinary rooms; they give a first harvest within weeks.
Summary
Sources and credits
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
