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Mushroom soft delicate white
fruit body of fleshy fungi, of the family Agaricaceae. The real plant
is the microscopic fine thread-like body called mycelium, grows on the
substratum or under the surface of soil. After maturity the mycelia come
together in a very compact form and sprout as spreading umbrella like
structure. Majority of mushroom belong to Hymenomycetes of Basidiomycotina,
characterized by the presence of spore bearing hymenium layer below the
spreading structure, the gill.
The poisonous mushrooms are commonly known as toadstools.
Sometimes a species may be edible when it is young and fresh, may become
poisonous or inedible when it is overmatured and has started decaying.
The common edible mushroom belongs to some species of Agaricus
and Pleurotis. The common poisonous species are of Lepiota
and Amanita. Edible mushrooms provide a good addition to the diet
in the form of proteins, carbohydrates, valuable salts and vitamins, immediate
between meat and vegetables. Due to high protein and mineral contents
and low caloric value, it is recommended to heart patients. About 20 mushroom
species grow wild in Bangladesh, of which 5-6 are poisonous. Some mushrooms
grown wild are eaten by the tribals of the chittagong
hill tracts. Very recently some small-scale farms are cultivating
mushroom in the country.
Mushroom cultivation
Raising edible mushroom for human consumption. In the ancient Greek, Roman
and Indian culture mushroom has been described as delicacies associated
with royal class. The commercial cultivation first started in Europe with
the beginning of this century. Mushroom cultivation in Bangladesh is very
recent. In early 1980s commercial mushroom cultivation was initiated by
Bangladesh Agricultural Research Council and then a Mushroom Culture Centre
at Savar. The recommended cultivated mushroom is white button mushroom
(Agaricus bisporus) and oyster mushroom or wood fungus (Pleurotis
sajor-caju, P. flabellatus, P. ostreatus).
The oyster mushroom is common and favourite in Bangladesh. The main raw material for growing is a composite mixture of rice straw and rice husk, saw dust and cotton waste, and some other agro-residues. It is grown in the polythene chamber in thatched hut or in pucca house. The whole process requires about 35 days. After planting, harvest is done in 10-15 days. It is cultivated throughout the year but the oyster mushroom is cultivated in winter season. For cultivation of pure mushroom, spawn or seed (spore) is essential. The temperature required for good growth is
20°-25°C at the beginning and 10°-18°C at the fruiting stage. Harvesting is done at the early stage of fruiting just before the spreading of umbrella-like fruit body. From a single cultivation bed continuous harvesting is done up to two weeks. The bed can be recycled to some extent. The fruit body is taken fresh or dried for long preservation.
The paddy straw mushroom is summer type (Volvariella
diplasia, V. volvacea and V. esculanta). The requirements for
the culture bed are more or less similar to that of oyster mushroom but
the temperature needs to be 35°-40° C. At present the production cost
is about Tk 50-60 and the market value is about Tk 150-200 per kg.
[Mostafa Kamal Pasha]
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