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1- SME'S IN ECONOMIC DEVELOPMENT
2- FACTORS AFFECTING GROWTH OF AUTO SECTOR
3-
TEXTILE: BUMPER COTTON CROP
4- AUTO SECTOR NEEDS EXPANSION
5- CULTIVATION OF OYSTER MUSHROOM IN PAKISTAN

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CULTIVATION OF OYSTER MUSHROOM IN PAKISTAN

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Bright prospects

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By M. Mithal Jiskani, Assistant Professor (Plant Pathology), Sindh Agriculture University Tandojam

Sep 13 - 19, 2004
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The mushroom is a form of plant life, recognized as fleshy fungi, sometimes tough, umbrella like sporophore (fruiting body) with spores. The terms pore fungi, morels, tooth fungi, club fungi, smooth fungi, puffballs, stink horns, jelly fungi and cup fungi as well as toadstools or truffles have been use to refer to edible or poisonous mushrooms.

There are thousands of mushroom varieties found throughout the world, of which about 2500 species are reported to be edible. So far, only 20 species have been brought under cultivation, of which only eight are cultivated for commercial purposes. The cultivation of mushrooms for food is an old and worldwide practice. They can be cultivated successfully on a small or large scale, under artificial conditions with little water, in a small space either indoor or out of the door. Plant residue, waste of forestry and agricultural as well as industrial waste and other refuses, rubbish or trash can be utilized as substrate for cultivating mushrooms. In this manner, the growers would be able to produce nutritious food and beneficial medicine.

The mushrooms, Pleurotus spp. resemble with the shape of oyster, therefore mostly known as oyster mushroom in English, Sipi Khumbhi in Sindhi, Sadafnuma Khumbhi in Urdu. It is also known as Wood mushroom, Dhingri, Henda, Kharari, Shooto and Meat of the forest, because of its growing habit, habitat, food value and so. According to Alexopoulos and Mims (1979), Pleurotus spp., the oyster mushroom, is a member of Tricholomataceae family, belongs to order Agaricales, subclass Holobasidiomycetidae II (Hymenomycetes II), class Basidiomycetes, subdivision Basidiomycotina, division Amastigomycota, kingdom Mycetae (fungi), relates with organisms have a membrane bound nucleus, stood under super kingdom Eukaryonta.

IMPORTANCE

The chemical composition of the fresh fruiting bodies of the different species of Pleurotus, the oyster mushrooms, indicates 16.43 to 39.93% proteins, 0.94 to 2.07% fat, 0.90 to 14.10% crude fiber, 0.85 to 31.22% ash and 87.50 to 92.47% moisture (Ramzan, 1982 and Hafiz, 1986). Bahl (1994) quoted that this mushroom contents 92.5% moisture on an approximate fresh weight basis, while vitamins such as 4.8 mg thiamin, 4.7 mg riboflavin and 108.7 mg niacin; minerals like calcium 98 mg, phosphorus 476 mg, ferrous 8.5 mg and sodium 61 mg per 100 g dry weight basis.

Justo, et al. (1999) also evaluated the protein quality of fruiting bodies of three Pleurotus ostreatus Mexican strains and reported that protein concentration ranged from 17.26 to 19.97 g/100g dry weight; chemical scores were between 74 and 39% with available lysine as a first limiting amino acid. The nutritional evaluation revealed 67.75 to 68.38% in vitro digestibility. Relative protein values were from 100.6-107.85%, which were lower than soybean meal and whole egg but larger than those of rice, maize, beans, fava beans and pesta, no differences were found between these values and those of skim milk powder, casein plus methionine and albumin. They concluded that due to their essential amino acids content, mushroom proteins are a good compliment of cereals; furthermore, it is highly recommended to include Pleurotus in the daily diet. Rambelli and Menini (1985) reported that this mushroom is reputed to be antitumoural because of its chemical composition.

According to Raven and Johnson (1992), the mycelium of the edible oyster mushroom, P. ostreatus, excretes a substance that anesthetizes tiny round worms known as nematodes, that feed on the fungus (oyster mushroom). When the worms become sluggish and inactive, the fungal hyphae envelop and penetrate their bodies and absorb their nutritious contents. It means that this mushroom may also play a vital role to control nematodes biologically. On the other hand, Tsuda, et al. (1996), reported that some of the nematodes inhabit and lay many eggs inside the gills of oyster mushroom, Pleurotus ostreatus and cause a disease known as gill knots. The fungus gnat Rhymosia domestica (Mycetophilidae, Diptera) was confirmed to be the vector of the nematode inside the gill knots.

 

 

CULTIVATION

The first time artificial cultivation of oyster mushroom was started in China during 1950 on dry wood logs and its commercial cultivation was started from 1971. Nowadays it is successfully cultivated on commercial basis in almost 80 countries and is becoming an important industry throughout the world (Choudhry and Shaikh, 2000).

According to Jiskani (1999 and 2001), different agricultural and or industrial straw wastes can be converted into edible oyster mushroom, because this mushroom is grown under natural conditions on living trees as parasite or dead woody branches of trees as saprophyte and primary decomposer. Mostly, the wheat, paddy, barley, oat and gram straw, banana, sugarcane and maize leaves, empty millet heads and corn cobs, cotton waste, thin sticks and boll locules, sugarcane baggage, banana pseudostems, saw dust, logs, straw papers, manure etc. can be used as substrate (medium) for its cultivation. As Pakistan is an agricultural country, therefore a huge quantity of the crop wastes is easily available at low cost, which could be converted in to edible oyster mushroom, by using separately or in combination.

SUITABLE PLACES AND/OR MODEL MUSHROOM HOUSE

Mushrooms can not be grown year after year with full commercial excess, unless proper growing conditions are provided and adequate facilities are available, for the control of diseases and insect pests. Such conditions can be fulfilled in shelf growing, by the construction of properly insulated and ventilated mushroom houses. Model mushroom house must have: store room, pasteurization room, spawn preparation and spawning room, spawn running room, cropping room as well as packing and preservation room.

However, it may also be grown in a variety of places like: ditches, caves, huts, hovels, cottages, cellars, garages, sheds or shelters, bee hive shaped huts, thatched or meted roofs, thick tree groves and gardens. Kitchens, bathrooms or other extra rooms of a house or any other vacant building can also be used for the same purpose.

METHODS AND CONTAINERS

Cultivation of oyster mushroom in polyethylene bags under controlled temperature, humidity and light proved to be the best as compared to other methods and containers. The cylindrical beds on circular metallic stands, earthen pots, soil bunds and beds, bundles, cane baskets, trays, shelves, frames, cassettes, chicken wire towers etc. are also commonly in use, for cultivation of oyster mushroom.

MUSHROOM SPAWN

The best spawn can be prepared on sorghum grain but other cereal grains as well as all agricultural and industrial wastes, recommended for the cultivation of oyster mushrooms can also be used. The entire operation (spawn preparation to spawning) begins in a laboratory under sterile conditions. The spores or natural seeds of the mushroom are so small, which could not be seen with necked eye, therefore, the mushroom grower cannot handle them. Laboratory person could inoculate sterile cereal grains with the spores or pure mycelial culture of the mushroom and incubate that until a viable product is developed. The grains become "spawn" and can be sown like seed.

PROCEDURE

Chop the straw, leaves and empty corn cobs in to small pieces of about 3-5 cm. Threshed wheat straw, cotton waste, saw dust, cotton boll locules and empty millet heads or so, may directly be used by soaking them in water for 24 hours separately or in combination. After chopping of straw or leaves as well as soaking of waste, what ever be selected for use, boil the same (selected waste or substrate) in water for 10-15 minutes, for killing of insect pests and other microbes present in the selected substrate and also for moistening of the substrate. Now take out the straw from water and spread it on the inclined cemented floor for cooling as well as removing of excess water from the substrate. When the temperature droops down to about 20oC and moisture content becomes about 80-90%, add 1% lime and wheat brain in cotton waste or saw dust in order to adjust pH of such substrate. After such process, fill the ready substrate in polyethylene bags and sterilize in an autoclave at 15 lbs. psi for one hour so that the material may be obtained sterilized. After completion of sterilization and when the temperature becomes down up to 20oC, the spawning should be done at the rate of 7-10% of the substrate dry weight (which will be 70-100 gm /kg) under aseptic conditions (in isolation chamber). Now the spawned bags should be placed in spawn running room under controlled temperature, humidity and light (see table). After completion of the spawn running and the formation of pinheads (initial growth of fruiting bodies) of the mushrooms, open the mouth of the bags, to facilitate the growth of fruiting bodies. Sort out the contaminated bags and destroy them away from the growing space. Burning of such material should be safe for remaining crop.

TABLE:
HUMIDITY AND TEMPERATURE REQUIREMENTS FOR THE CULTIVATION OF OYSTER MUSHROOM

GROWTH PERIOD

HUMIDITY (%)

TEMPERATURE (OC)

PERIOD (DAYS)

Spawning to spawn running

80 to 90

23 to 26

15 to 30

Pinhead formation

80

14 to 18

10 to 20

Cropping

85 to 90

15 to 20

28 to 42

 

 

HARVESTING

Oyster mushroom yields the crop in cycle, hence subsequent flushes of the fruiting bodies can be harvested till the conversion of waste in to mushroom or up to contamination or till attack of insect pests or diseases. However, harvesting could be done with the help of sharp knife or blade, at the base of the stipe (stem or stalk), but the stalk should never be cut on the bed. The solid portion of mushroom left on the bed may become a harbor for flies and other insects, hence, should be removed. All mature, harvested or diseased mushrooms, their stalks and refuse must be removed at every harvesting; from the house and destroyed, to minimize risk of the development of the diseases and pests.

If there are many pinheads around the mushrooms (the mushrooms, which are to be harvested), then cut only mature mushroom very carefully, so that the near by pins do not be disturbed. Otherwise, these pinheads will not grow, but will turn yellow, finally, many saprophytes may attack these pinheads and diseases will spread.

YIELD

Approximately, this mushroom yields 100% of substrate dry weight, it means that one kg of fresh oyster mushroom can be obtained from one kg of dry substrate (before soaking or boiling of straw waste).

MARKETING

The artificially cultivated oyster mushrooms could be marketed in local and foreign markets.