In this article we will discuss about:- 1. Introduction to Mushroom 2. Edible and Poisonous Mushroom 3. History 4. Cultivation in India 5. Morphology 6. Types 7. Spawning.
- Introduction to Mushroom
- Edible and Poisonous Mushroom
- History of Mushroom Cultivation
- Mushroom Cultivation in India
- Mushroom Morphology
- Types of Mushroom
- Spawning of Mushroom
1. Introduction to Mushroom:
Fungi are a very distinct group of organisms. The vast majority fungi are minute, many only visible to the naked eye as mats of cotton-like threads such as blue mould of Penicillium often found on stale bread. It is impossible to identify these fungi without aid of microscope. For most of us however, the word “fungus” conjures up an image of mushrooms and toadstools that are found growing on our woods and field.
Many of the fungi are the decomposers of our environment and they are just as important as the green plants, which are the producers. Fungi lack green pigment, chlorophyll, found in green plants and some algae. It is this pigment that is essential in converting the energy of sunlight directly into the form that is available for use by these higher plants. Because of fungi do not have this pigment they must obtain the energy required for their life-giving processes indirectly from other sources.
Fungi basically utilize the organic materials produced by other plants and animals in two ways. They may feed on dead or decaying organisms or the products of thereof, weather this be the dead trunk of tree, the decomposed remains of the a plant in the soil, a dead insect or man made products derived from plants and animals, such as food stuffs and clothes.
Most of the fungi are the mushrooms or toadstools and few people realize that without fungus, which is only visible to the eye for a short time each year as large fruiting body many of our woods and forests would not exist in the form today.
Mushroom is a simple form of life known as fungus. They are alike for their flavor and high food value. There are different views in regard to the origin of the term “MUSHROOM”. In Latin “fungo” means to flourish. Previously it was believed that mushrooms were some excrescences from the ground or from trees. “Mushroom” term was derived from the Greek word “sphonggos” or “sphoggos” means sponge like structure.
The Greeks used the word ‘Mykes’ for mushroom generally and the science of fungi or mycology etymologically is the study of mushrooms (mykes – mushroom + logos-discourse). It was also thought that the term is from the French word “mousseron” (Muceron) “mousse” or “moss”. The other views are “muscheron” and “mouscheron” which it is easy to understand how the familiar name of “mushroom” practiced.
Many spices are found in widely separated geographical areas. The Agaricus campestris the common field mushroom grows in open fields. Agaricus rodmani (Rodman’s mushroom) is an urban inhabitant found on city lawns and very frequently next to the curb or city streets.
Marasmium oreades, the fairy wing mushroom, is also common on city lawns, forming rings of mushroom on the grass. Some species prefer wooded areas; Collybia longipes the long-rooted mushroom is generally found on the ground in most woods; Collybia velutipes, velvet stemmed Collybia grows on dead wood-logs or cut lumber from spring to late fall.
The question which the prospective mushroom hunter will first ask is – “How can I distinguish between edible and poisonous species?” The only answer to this question is that there is no known test to which you can subject an unknown mushroom specimen to learn either it is edible or not.
There are many traditional methods for testing these fungi but they are unreliable. It was believed that mushrooms which grow in the meadows were edible and these which grow among rusty nails rotten eggs, near serpent holes or trees producing poisonous fruits were not edibles.
The belief was a prevalent that edible fungus peeled off easily and do not change a silver spoon black while cooking. This belief is incorrect as Amanita phalloides, which is poisonous, peels off easily and the silver spoon remains unaffected.
There was assumption that brightly colored mushrooms were poisonous where as white or creamy one’s were edible. This is also wrong as “Chanterelle” (Cantharellus eibarius) and “wood Belwits” (Trieholoma nuduns) even though bright coloured are quite safe to eat whereas “Death cap” (Amanita phalloides)” “fools mushroom” (Amanita verna),”Destroying angel” (Amanita verosa) are completely white and deadly poisonous.
Another assumption was that feeding doubtful specimens to pet animals is also useless as the reaction may be different or slower in these cases. It is not safe to believe that fungi, which have been nibbled by slugs or larvae, are not poisonous; on the contrary, slugs seem to be particularly fond of Amaita phalloides and the stomach contents of rabbits are able to neutralize the poison of the most dangerous species.
All species of the particular genus are not edible. From the genus Agaricus the common edible species are A. arvennsis and A. compestris and whereas A. xanthoderma is poisonous.
Some genera having many poisonous species may also have non-poisonous species, for example Amanita includes the highly poisonous species A. phalloides, A. vera and A. verosa and it also includes the edible species A rubscense.
Morphologically similar mushrooms may show close similar characters but one may be edible and the other may be poisonous. For example Lepiota margani is a poisonous mushroom and if eaten causes a fatal illness whereas Lepiota rachodes is edible and delicious. All the characters are similar except that at maturity L. morganni (Poisonous) have green and pale green spore, whereas the spores and gills of L. rachodes are white.
Mushrooms may become poisonous if eaten with alcohol. For instance purplish red skin discoloration may occur as a temporary result of eating the “Ink cap” (Coprinus atramentarius) variety with alcohol.
Mushrooms are popular for their delicacy and flavor rather than food value. However, it is an established fact that they are excellent source of vitamins and minerals. In view of their very high food value to man and their medicinal properties, mushrooms can help in solving the problems of malnutrition and diseases. They contain appreciable amounts of Niacin and Pantothenic acid.
Minerals such as calcium, phosphorus and potassium are also present with a fair quantity of iron required by the human body. Folic acid, which is of vital importance for treating anemic conditions in the human body, is available in large quantity.
Their protein may be considered intermediate to that of animals and vegetables with very low starch content, the mushrooms are an exceedingly useful for diabetic patients. Indeed with low carbohydrate and fat contents, they constitute an ideal dish for those who wish to lose weight.
Mushrooms have more scope due to above-mentioned nutritive value but method of cultivation is also equally important. Cultivation of mushroom is an art obtaining maximum production at minimum cost.
3. History of Mushroom Cultivation:
Greek people practiced mushroom as food for the first time. Bonnefons in 1650 invented for the first time mushroom cultivation. In the year 1952 Culpeper’s wrote a book ‘Complete Herbal’ in which he mentioned about mushroom cultivation.
Treschow pointed out that shortly before 1700 it was a fashion to grow melon and pineapple in hot bed under heat; spontaneous and frequent appearance of Agaricus bisporus in composted manure in the hot bed was observed several times. Frenchman de Tourneforte, wrote and published description and how to grow mushroom in Paris in 1707. The methods explained by him are similar to today’s methods. Abecrombine in 1779 wrote a book on mushroom cultivation.
In 1800, the French started growing mushrooms underground in the quarries around Paris on horse manure, which was stacked in heaps and allowed to heat up naturally. The resulting compost was laid down in long ridges and inoculated with spawn dug from meadows or mill tracts where horses had been trampling. It was just matter of chance if one got a mushroom crop from that compost.
The people from England, France and You rope brought the mushroom cultivation technology in America. During the year 1885 these people started mushroom cultivation in green house at New York. Seren Rasmussen in the year 1892 started mushroom cultivation at Westtown. He in 1894 demonstrated mushroom cultivation in a room.
French mycologist, among them Matrochot and Costantin (1894), succeeded in solving two important problems in mushroom cultivation. First they discovered the cause of mushroom disease, la mole (Mycogone perniciosa Magnus) and started fumigating sulphur; and secondly, they were able to germinate spores for the purpose of obtaining sterile spawn.
This was probably the most important contribution to scientifically controlled mushroom growing. The process was patented but did not appear to have been commercialized, and in 1902 Miss Fergusson of Corne described detail method for germination spores.
Duggar (1905) perfected in America a method of making pure culture spawn from mushroom tissue. This method was exploited immediately, for the Americans realized that now it was possible to select and guarantee a particular strain. From that moment mushroom growing began to develop into the highly scientific industry that is today.
In 1918 the U. S. marketed pure spore culture bottled spawn introduced by Lambert. Although in the latter years of the last century French growers had discovered that ground gypsum (calcium sulphate) prevented greasiness in the compost, it was Pizer, who, at Wye College in 1936, discovered the reason. The addition of gypsum to all compost is now universally practiced which immensely improved spawn growth. Lambert and Sinden were working on synthetic composts. Sinden patented his grain spawn process in 1932.
In 1945 a number of specialists calling themselves the midlands Group of Mushroom Growers held series of meetings to discuss the problem facing the industry resulting before long in the formation of associations like M.G.A. (Mushroom Grower’s Association of England and Ireland) as specialist branch of National Farmers’ Union; M. R. A. (Mushroom Research Association Ltd.), was launched to investigate the cultural problems; and the M. G P. (Midlands Group of Publication) was established to commission authoritative leaflets on the technical aspects of commercial growing and to publish the M. G A. bulletin.
In India probably in 1886 some fine specimens of mushroom were identified and grown by N.W. Newton and exhibited at annual show of Agricultural Horticultural Society of India at Calcutta. Bose (1921) was successful in culturing two agarics on a sterilized dung medium, details of which were published in the Indian Science congress held at Nagpur during 1926.
The method of growing mushroom on horse manure was discussed in detail by Bose and Bose (1940). Later Padwick (1941) states the cultivation of A. bisporus was tried all over the world. However the first successful attempt at cultivation of a paddy straw mushroom (Volvariella diplosia) was made by Thomas and his group at Coimbatore in 1943.
In 1962, Bano et al obtained increased yield in Pleurotus species on paddy straw. However first systemic effect in cultivating button mushroom was made in 1961 in the state of H. P., where a scheme entitled “Development of mushroom cultivation in Himachal Pradesh” was started at Solan by H. P. State Government in collaboration with I. C. A. R. In 1964 experimental cultivation of A. bisporus was started by CSIR and J & K Govt. in Srinagar.
During 1965, Dr. E. F. K. Mantel, FAO, mushroom expert, assisted Department of Agriculture. H. P. in the construction of modern spawn laboratory and fully air-conditioned mushroom house. Research on evaluation of different strains and use of various agricultural waste and organic manure and fertilizers for preparing synthetic compost was undertaken.
In the year 1974, services of another FAO expert W. A. Hayes, were obtained for further improving the method of compost preparation, pasteurization and management of various parameters in mushroom house. New compost formulation, casing material and study of important parameters in the compost, use of spent compost and farm yard manure as casing soil, aeration and maintenance of proper environmental conditions were also undertaken which raised the mushroom yield from 7 to 14 Kg/m2.
In 1977, a 1.27 crores Mushroom Development Project was launched under aegis of the U. N. D. P., by the Department of Hort. (H. P.) where the services of Mr. James Tunney were made available at Solon. With construction of bulk pasteurization chamber, he made ready pasteurized compost available to the growers of Shimla, Solan and Sirmour district of (H.P.).
With the termination of UNDP, project in 1982, the Dept. of Horticulture (H.P.) is successfully running the project. In 1982, Indian Council of Agricultural Research, sanctioned the centre for Mushroom Research and Training during VI plan on October 23, 1982 with the objectives of conducting research on problems of mushroom production, preservation and utilization and to impart training to interested personnel. The center started functioning w.e.f. 8.6.1983.
Simultaneously ICAR sanctioned six, all India coordinated Mushroom improvement project in the year 1983 at GBPU of Agricultural and Technology Pantnagar (U. P.), PAU. Ludhiana (Punjab), TNAU, Coimbatore (TN). BCKVV Kalyani (WB), MPAU, College of Agriculture, Pune (MS) and C. S. Azad Univ. of Agriculture and Technology Kanpur (U.P.). In subsequent years, Kanpur and Kalyani centers have been deleted and IGKVV, Raipur (Chhattisgarh) has been added.
After 1970 advances in mushroom cultivation technology without any difficulty and marketing from various states cultivation on commercial basis going on are Himachal Pradesh, Haryana, Jammu & Kashmir, Punjab, Tamil Nadu, West Bengal, Maharashtra, Uttar Pradesh, Orissa, Madhya Pradesh, and Gujarat.
5. Mushroom Morphology:
Mushrooms are the reproductive bodies/fruiting bodies formed by certain fungi, belonging to the group Basidiomycotina and Ascomycotina. The Mycelium, of these fungi is found in the growing substrate, which may be a dead tree stump, a live tree, or organic material in the soil.
Fungi reproduction depends on the existence of specific environmental conditions, especially the moisture or humidity level, the temperature, and the availability of nutrients. Optimum conditions vary among species. Under the right conditions “fruiting” occurs and the mycelium produces mushrooms. When mature, the mushrooms release millions of spores into the environment for further propagation of the species.
Fruiting bodies of the fleshy fungi are termed as mushrooms. The scientific term used to describe the main body or thallus of fungus is mycelium. This is a mass of delicate filaments called hyphae. These hyphae can penetrate various types of material ranging from woodland humus and rotting wood to the tissues of living plants. In some fungi the mycelium develops into mass of thin or thick roots, threads or even thick cords.
The mycelium obtains nutrients from decomposing organic matter. Some types of fungi grow on their mycelium hardened, tuberous, globular or irregular formations, which have dark surface. They are called sclerotia and store reserve food material and enable such fungi to survive even in unfavorable growing conditions. In some fungi these sclerotia can latter develop into fruit-bodies. The life of mycelia varies considerably; some live for one to two years, others for several years.
The mycelia of other fungi, such as the Fairy-ring champignon (Marasmius oreades) or Blewits (Lepista saeva), spread evenly in all direction over the ground so that after a number of years they form very large circle, whose fruit body start to develop at certain times during the year. At ground level it may be difficult to see that they do in fact form circle at all.
Aerial photography on the other hand often reveals these old fungus circles very clearly because of the darker colour of the grass at edges of the circle. These circles are sometimes popularly thought to have magical qualities and are known as fairy rings. However, the most distinctive mycelium is that of the Honey fungus (Armillaria mellea), which grows thick, dark coloured, branched rhizomorphs rather like bootlaces covered by a shiny, hard skin.
The majority of mushrooms belong to Hymenomycetes of Basidiomycetes, characterized by the presence of spore bearing layer known as Hymenium. The thallus/Fruiting bodies of mushroom are distinguished in cap/pileus, gills/lamellae, veil, stipe/stalk, and volva.
The pileus is formed as an expanded portion of the apex of the stipe. In it the hyphae of the cap surface and of flesh are the same size and are interwoven. Such pileus is described as homogenous. In other pileus homogeneous beneath a differentiated cuticle and in a few there are differentiated layer in the trama itself. Sometimes it may be thick, fleshy, cocky or membranous and varies greatly in shape, size and colour. The surface of the pileus may be smooth, hairy or rough.
Gills or lamellae are specialized compact layer of tissue giving rise to the hymenium is technically known as the subhymenium. These are often distinct present on the underside of the pileus starting from apex of the stalk and radiate out towards the margin. In many species the gills are distinctly coloured. These gills bear spores on their surface and exhibit a change in colour corresponding to that of the spores.
The attachment of the gill to stipe helps in the identification of the mushroom. When gills do not touch the stipe or only do so by a fine line they are known as free. When they are attached directly to the stem, forming nearly a right angle with latter, they are termed adnate. If the attachment is only by a part width of the gills, they are annexed. When the gills extend down the stem to a greater or lesser degree they are known as de-current and when they are near stalk in a deep notch they are termed as simuate.
The center of the gills is made up of mycelial thread known as Trama; these threads may run parallel to each other or may interwoven. Accordingly, cells may be long or short.
The Cystidia, Basidia and the Paraphyses together constitute the Hymenium.
Towards outside of the trama, the cells branch into short cells forming a thin layer, the Subhymenium.
The subhymenium gives rise to long club-shaped cells, which are parallel to each other and at right angle to the surface of the gills. These club-shaped cells are called Basidia which have 2 to 4 spine like projections, the sterigmata, on which Basidiospores are borne.
The basidiospores can be of different shape globose to elongated in length from 2 to 40μ with rough or smooth margin. The colour of the spores is from colourless to black. Many spores give an amyloid reaction with iodine. This test is used in classification of Agaricales.
Among the Basidia there are many sterile cells. Some inflated bladders like projecting beyond the basidia are the Cystidia.
Projecting beyond Basidia are the Paraphyses.
The veil is nothing but the margin of young pileus is connected to stem or stipe by a membrane. As the basidiocarp grows the upper portion of button expands in to the cap or pileus the inner veil tears, it often becomes severed from the margin of pileus and remain attached to the stem in the form of a ring or annulus.
In certain mushrooms whose development is somewhat different, the inner veil tears, portion of it hang down from cap like a thin, cobwebby curtain, the cortina. It is very delicate and can be easily be rubbed off or may even be washed away by rain.
The stalk supporting the pileus is also known as stipe. Broadly speaking the structure of stipe is differentiated into two parts-outer cuticle and inner cortex. The structure varies with genus and species, but basically the hyphae, at least cortical region are more or less perpendicular in arrangement. The stem may be solid, fleshy throughout or may be hollow in which the central cavity is stuffed with pithy substances.
Its presence or absence and mode of its attachment to the cap is an important character of identification of genera. Mostly the stem is centrally attached to the cap. But in some cases the attachment may not be exactly in the middle but lateral, than it is known as eccentric.
The stipe having the same diameter throughout length is called cylindrical but swollen in the middle and tapering towards both the extremes is considered as spindle shaped and club shaped when it enlarges towards the top and tapers towards the base into root like form. In the marginate the stipe base widens into a sort of saucer with well-defined margin whereas in bulbous stipe the base shows a sudden enlargement.
The cuticle is either composed simply of more or less longitudinally arranged, closely packed smooth narrow hyphae with or without slightly thickened walls. Such a stipe is described as naked. In other cases projections develop from the cuticular hyphae and simply project outward.
Initially the entire fruit body prior to differentiation is covered by universal veil. When the sporophore enlarges and the pileus finally expands, the veil tears in such a manner as to leave a cup- shaped body, the volva around the often, bulbous base of the stem. Or some portion of the entire veil tissue may remain as scales or marks on the expanded pileus.
According to the presence or absence of annulus and volva, the mushrooms can be put in the following four categories:
i. The mushroom in which both annulus and volva present as Amanita.
ii. Only annulus present and volva is absent as in Agaricus.
iii. In which volva is present and annulus is absent as in Volvriella
iv. In which both annulus and volva are absent as in the common fairy ring (Marasmius oreades).
Mushrooms are classified into three types according to their growing characteristics:
They attack a living host plant, usually a tree, and eventually kill it. An example of a parasitic mushroom is the Honey mushroom (Armillaria mellea). This type of mushroom can be cultivated but will require a living host.
These mushrooms form a symbiotic (mutually beneficial) relationship with the roots of trees or shrubs. Examples include the Boletes, Truffles, Chanterelles, and Amanitas. Cultivation of this type of mushroom requires the other half of the symbiotic relationship, which is the live tree. It is almost impossible to establish this symbiotic relationship under controlled conditions on a commercial basis.
However, success has been achieved with truffles whereby a grower inoculated the roots of small oaks with the mycelium, planted them, and then waited for more than ten years before harvesting the truffles.
They grow on dead organic matter such as dead trees, stumps, old roots, grass, straw, compost, etc. Mushrooms in this group are those that are successfully cultivated including Shiitake, Oyster, Champignons or White Button mushrooms (Agaricus spp.), Portobello, Enokitake, Reishi, Maitake, Paddy Straw mushroom, and many others.
7. Spawning of Mushroom:
Higher plants reproduce by seeds; like that mushroom reproduces structures are called the spawn. The vegetative mycelium from a selected particular strain of mushroom decides the type of mushroom spawn. The mushroom first grown on proper medium; segments of living mycelium inoculated on sterilized starchy seeds in sterilized condition; the growth of it on seeds is called “spawn”. The success of mushroom cultivation and its yield depend to a large extent on the purity and quality of the spawn used.
Methods of Preparation of Grain Spawn:
Sorghum, wheat or bajra fresh, healthy, untreated grain should be used for making spawn. The selected grain should be boiled with equal amount of water till the water dries up. Softness of boiled grains should be taken into account.
Split or starch ooze out should be avoided. The soft seeds should be air dried and treated with calcium carbonate @ 8 percent by the grain weight. The mixture is filled in wide mouth bottles and plugged with non-absorbent cotton tightly and sterilized at 15 lbs p.s.i. for half an hour.
The calcium carbonate absorbs excess of water thus helps in keeping the grains separate. It also helps in maintaining the pH. The bottles should be carefully observed for contamination and inoculated with mother culture of mushroom.
The best incubation period is 21 days at 25 ± 2°C. By this time grain become covered with mycelium. The combination of 2 percent gypsum and 6 percent lime by grain weight gives the best results in the process of making grain spawn.
Kinds of Spawn and Material Used:
i. Virgin Spawn or Natural Spawn:
The natural spawn was used for inoculating the bricks in the manufacture of brick spawn and flake spawn in addition to the planting bed.
When the spores of the mushroom fungus fall on suitable substrate and the environment is also suitable, they germinate and form a mat of mycelium. This is dug out and used as spawn, and is known as “Virgin spawn”. This type of spawn was used in France and exported to other countries.
ii. Flake Spawn:
The flake or flakes were commonly known as French spawn because it was extensively manufactured in France. When the beds are fully covered with mycelium before a crop of mushroom appears, the compost is collected, broken, dried and used fresh to inoculate other new collected, broken, dried and used fresh to inoculate other new beds. This type of spawn is called flake spawn.
iii. Brick Spawn:
This is called because the material in which the mycelium is present is in the form of brick. The brick measuring 5″x 8″x 1.5″ weigh about 1.5 pounds each when dried. A mass consisting of horse and cow dung manure and loam is mixed with water, tapped out in layer two inches thick and cut into pieces when half dry.
These pieces are then inoculated with the old spawn by making a hole in each, and after the spawn grows through the entire piece, it is dried and sold as brick spawn. Mycelium from tissue cultures is inoculated into the bricks and thus a vastly improved laboratory type of brick spawn is prepared.
iv. Grain Spawn:
The grain spawn is now almost universally used. Sinden (1932) introduced grain spawn with addition of calcium salts to hard winter rye grain. Stoller (1968) got a faster growth of the mycelium of hulled grain and cotton seed meal, while on buck wheat and wheat grain be obtained poor results. Another type of spawn that has been developed is spawn using grain wheat as a base.
The larger grains carry a greater reserve of food material per grain for mushroom mycelium so the spawn prepared with larger grains can with stand adverse conditions such as poor composting etc. The small grains provide more points of inoculum per gram of spawn, so the spawn prepared with smaller grains will cover the compost sooner. Munjal (1973) recommended use of Jawar grains for preparing spawn of A. bisporus.
The mushroom yield is always proportional to the method of spawning.
There are various methods of spawning are as under:
(A) Layer Spawning:
Layer spawning is of two types viz. single layer and double layer spawning. In the single layer spawning; only one layer of spawn is placed in the middle of compost, where as in two layer spawning two layers of spawn are given one at the middle of bed/tray and the other at the top of bed/tray.
(B) Top Spawning:
The spawn is sprinkled just above the top surface bed/tray. To avoid drying of spawn a layer of compost should applied above the spawn layer.
(C) Through Spawning:
The compost or straw is thoroughly mixed with spawn and filled in the tray or beds.
(D) Shake-Up Spawning:
After one week of spawning the compost is thoroughly shaken up, and replaced in the in trays. After that either it is cased at once or a few days later.
(E) Active Mycelium Spawning:
This method fully grown spawned compost bed/tray with fresh mycelium are used for spawning further trays. One such tray is sufficient to spawn several other trays. In this method, however, chances of contamination are more.
(F) Spot Spawning:
In the straw filled beds or compost filled trays, holes at a certain distance are created with a pointed stick or fingers and spawn is put in.