INTRODUCTION

Oyster mushrooms represent basidiomycetous fungi,

characterised by edible fruit bodies with eccentric stalk

attached to the pileus that opens like an oyster shell during

morphogenesis. These mushrooms namely Pleurotus species are

described as 'food delicacies' because of their characteristic

biting texture and flavour.

Cultivation of different species of oyster mushrooms around

the world represent the commercial, large scale conversion of

lignocellulosic residues into food. These mushrooms are the

efficient producers of food protein from worthless plant wastes

owing to the degrading ability of lignocelluloses. Unlike

button mushrooms, these oyster mushrooms do not require composted

substrates for their growth.

These mushrooms can be grown successfully in areas under

controlled temperature and humidity. Fresh mushrooms will be

collected in three pluckings from the plant residues during a

short span of time. They can be grown ideally in villages and in

urban areas. This is a simple low cost technology resulting in

higher productivity and monetary returns. Accordingly it has a

great prospect to emerge as an excellent cottage industry. It

can provide employment opportunities for men, women and un-

employed youth and also supplement the income of the farmers

during the lean months of farming. Being an indoor activity, its

cultivation is a boon to landless, small and marginal farmers

having uneconomic land holdings. As its consumption is

increasing world over owing to its nutritive value, it has good

opportunity in finding foreign market thereby earning foreign

exchange.

The spent substrate can be utilized for manuring and

fertilizing the crops as it is enriched with nitrogen .This is an

environmentally friendly technology as it helps in

biotransformation of waste biomass which, when left untreated,

will pollute the atmosphere.

Different species of Pleurotus were identified by several

workers based on their morphology and growth pattern. Some of

them are : Pleurotus citrinopileatus (Fr.) Singer. (Sivaprakasam

et al.,1986; Pareste,1987; Nair,1990); Pleurotus florida JACQ.

(Zadrazil,1982; Bano and Rajarathnam,1982; Pandey,1991) ;

Pleurotus saior-caiu (Fr.) Singer. (Jandaik and Kapoor, 1975) and

Pleurotus sapidus kalchob. (Atkinson,1961; Hard,1978; Bano and

Rajarathnam ,1987 and Marimuthu et al.,1991).

4

Several experiments have been carried out to standardise

the techniques of commercial cultivation of these oyster

mushrooms. (Jandaik, 1976; Rangad and Jandaik, 1977; Baskaran et

al . , 1978; Pal and Rajarathnam, 1982; Sivaprakasam and

Kandaswamy, 1982; Singh, 1983; Sivaprakasam et al., 1983; Garcha

et al., 19 85; Sivaprakasam et al., 1986; Bano et al., 19 87-a,-

Chauhan and Pant, 1988; Khader, 1988; Wood and Smith, 1988;

Bisaria et al., 1989; Kattan et al., 1990 and Marimuthu et al.,

1991) .

Though paddy straw and wheat straw were mainly used as

substrates for these mushrooms, various investigations have been

made on possible utilization of different plant residues like

straws,stalks, logs of woods,saw dust, dried leaves, flowers,

pods and agrobased industrial by-products. Bajra straw (Bisaria

et al., 1987; Goswamy et al. , 1987); banana pseudo-stem (Daniel

et al., 1991), cluster bean stalk (Bisaria et al., 1987); cotton

stalks (Balasubramanya, 1981; Lavie, 1988); fingermillet stalk

(Sivaprakasam and Kanadaswamy,1976);grass (Patil and Jadhay,

1991; Rao, 1991) karad hay (Rao, 1991); kudiraivali stalk (Daniel

et al., 1991); pearlmillet stalk (Sivaprakasam, 1987); spent

cotton stalk (Balasubramanya, 1989); spent straw (Sharma and

Jandaik, 1991); sorghum straw (Bisaria et al. , 1987); soybean

5

straw (Singh and singh, 1991); sugarcane bagasse (Bisaria et al. ,

1987; Azizi et al. , 1990); sugarcane trash (Patil and Jadhav,

1991) ; sunflower stalk (Patil and Jadhav, 1991) ; tobacco stalk

(Azizi et al., 1990); logs of wood such as vagai, cashew, silk

cotton, coconut, eucalyptus, jack, jambolana, litchi, mango, rain

tree, rose apple ((Suharban and Nair, 1991); sawdust (Block et

al. , 1958), willow saw dust (Balasubramanya, 1988); silk cotton

wood chips (Daniel et al. , 1991); dried fallen leaves like areca

leaf sheath (Chandramohanan et al., 1991); castor leaf (Madan et

al. , 1987); coconut leaf (Patil and Jadhav, 1991); cotton leaf

(Patil et al., 1989); green gram leaf (Patil and Jadhav, 1991);

mango leaf (Bisaria et al., 1987); mulberry leaf (Madan et al.,

1987) ; flowers of gul-mohr (Sivaprakasam and Kandaswamy, 1981) ;

pods of groundnut shell (Kala valli and Daniel, 1988; Khander et

al., 1991) and agro based industrial by-products like coffee pulp

(Pandey and Tewari, 1991); coir waste (Sivaprakasam and

Kandaswamy, 1981); oil palm factory waste (Kothandaraman et al. ,

1991); rubber processing waste (Kothandaraman et al., 1991);

sunflower husk (Savalgi et al. , 1991); tea waste (Pandey and

Tewari, 1991) and waste paper (Sivaprakasam and Kandaswamy,

1981) were also tried as substrates for mushroom cultivation.

While using various plant residues as substrates for oyster

6

ma>m»tmM

mushroom cultivation, influence of supplementation of substrates

with various organic and inorganic sources have also been

experimented.

Supplementation with locally available organic sources such

as tapioca starch, waste cotton, rice bran, v/heat bran (Ramasamy

and Kandaswamy, 1976) and other carbon sources such as dextrin,

glucose, ribose, arabinose, xylose, fructose, mannose, galactose,

sucrose, lactose, starch and mannitol were reported (Mukta Singh

et al. , 1990, Marimuthu et al. , 1991) .

Addition of organic nitrogen sources such as redgram powder,

horsegram powder, groundnut cake, soybean meal, alfalfa meal

(Ramasamy and Kandaswamy, 1971; Sivaprakasam and Kandaswamy,

1980; Zadrazil, 1980) and inorganic nitrogen sources like

potassium and sodium nitrate, (Jandaik and Kapoor, 1977);

ammonium nitrate; ammonium chloride (Khanna and Garcha, 1982)

were studied; oilcakes such as palm kernel cake, coconut cake,

cotton seed cake, mustard cake were also tried as supplements to

substrates (Gunasegaran and Graham, 1987; Vijay and Upadhyay,

1989). Apart from' these, silkworm litter (Madan et al. , 1989)

and dried neem leaves (Marimuthu et al., 1991) and neem cake

(Nallathambi, 1991) were also tried as supplements.

7

The food value of oyster mushrooms on the basis of their

nutrients was studied by various scientists (Edward, 1975;

Jandaik and Kapoor, 1975; Chang et al., 1981; Chang and Hayes ,

1982; Singh, 1983; Stanton, 1984; Sivaprakasam, 1987.b; Rai et

al., 1990; Bahl, 1991; Benjamin and Anuradha, 1991; Pandey, 1991

and Sharma, 1993) .

Based on their nutritive value, mushrooms are recommended as

best diet (Edwards, 1975). They are recognised by FAO(1977) as

food contributing to the protein nutrition of the countries

depending largely on cereals (Bahl, 1991); an ideal diet for

diabetics and blood pressure patients due to less fat and

carbohydrate content (Marimuthu et al., 1991; Pandey, 1991); a

low calorific food as recommended by NACNE (National Advisory

committee of Nutrition Education).

Mushrooms are considered food of delicacy not only for their

nutritive value but also for their colour, appearance, flavour,

taste and texture (Bahl, 1984; Bano et al., 1987; Marimuthu et

al., 1991; Khader et al., 1991).

Spent substrate of mushrooms can act as an organic manure

and thus help in substituting chemical fertilizer. Hence it can

conserve foreign exchange which is being incurred in importing of

8

chemical fertilizers. The natural lignocellulosic wastes degraded

by Pleurotus mushrooms could be used as garden manure as they

enrich the nitrogen content of the soil (Rangaswamy et al. , 1975;

Pal et al., 1979; Bisaria et al. , 1987; Mani et al., 1991;

Mathew, 1991; Pandey, 1991; Flegg, 1992, Zadrazil, 1992). They

release humic acid like fractions which when added to the soil,

increase its fertility (Rajarathnam and Bano, 1987).

The economic significance of this oyster mushroom

technology, due to its low investment and high return option was

investigated earlier (Bahl, 1984; Madan et al., 1987; Marimuthu

et al., 1991; Sudha, 1991; Kala valli et al. , 1993).

A simple technology easy to adopt, which can effectively

utilize the large quantity of crop residues, which when

effectively utilised would lead to pollution free atmosphere

besides contributing to the family income of the small farmers

simultaneously alleviate malnutrition arising out of protein

deficiency due to vegetarian diet, is the need of the hour for a

country like ours. This has been emphasised very much in various

reports (Singh, 1983; Bano and Rajarathnam, 1987; Bahl, 1988;

Benjamin et al ., 1991; Joseph et al., 1991; Nagarkar et al.,

1991; Nair, 1991; Pandey, 1991; Prakash et al., 1991; Suharban,

1991 and Kaul, 1993).

9

REVIEW OF LITERATURE

About 45,000 known species of fungi are recorded; of which

about 2000 are edible; of these less than 25 species are widely

accepted as items of food and only about a dozen of them have

been commercially cultivated. (Nair, 1990)

Oyster mushrooms are one among the cultivable varieties.

They are wide spread in temperate zones, can grow at moderate

temperature and are suitable to grow in most places in India.

(Atkinson, 1961; Hard, 1978; Zadrazil, 1982; Sivaprakasam et

al., 1986 and Bano et al., 1987)

Varieties of Oyster mushroom

The constant search for the appropriate oyster mushroom

species, suitable to varied localities of cultivation, providing

better taste and yield is indispensible. With this end in view,

the following species have been identified.

Pleurotus citrinopileatus Singer: It produces clusters of

whitish sporophores with central broad, spathulate to reniform

pileus that has irregular margins. The gills are adnate and

smooth, the stipe is short, cylindric and tomentose

(Sivaprakasam et al., 1986)*

Pleurotus florida JACQ: It has fruit bodies which are

smaller in size,finer in texture. Its color changes with

temperature from light brown to pallid yellow or white. Pileus

is soft,fleshy convex, smooth, whitish with shiny surface. The

stipe is short, solid, and laterally connected with the pileus

(Zadrazil, 1982; Rajathnam and Bano, 1987).

Pleurotus saior-caiu(Fr.) Singer: It produces grey coloured

fruit bodies either singly or in clusters. The pileus is oyster

shaped initially but becomes deeply lobed and folded at maturity.

The stipe is solid, rigid, eccentric and white in colour.

(Jandaik ejt al. , 1975) .

Pleurotus sapidus Kalchob: It grows in clusters, sometimes

they are scattered. Their colour varies from white, yellowish,

gray or brownish to lilac. Their pileus is convex, margin is

curved when young, wavy when old. Stipe is solid, attached to

the pileus near the edge. (Atkinson, 1961).

Cultivation of oyster mushroom

Cultivation of oyster mushroom is emerging in India as a

promising agro-based, independent enterprise owing to flexibility

of its operation and simple technology. Cultivation of different

varieties of oyster mushroom using paddy straw was reported by

11

many researchers. (Jandaik, 1976/ Pal and Thapa, 1979;

Sivaprakasam and Kandaswamy, 1980; Bano and Rajarathnam, 1982;

Kalavalli and Daniel, 1991; Marimuthu et al. , 1991) .

Constituents of substrate: Successful cultivation of these

thermotolerant basidiomycetes was found to be influenced by the

quality of the substrate and constituents of the substrate.

Good quality of paddy straw could give better yield as it

contains minimum weeds and moulds which would be killed at the

time of sterilization (Sharma and Jandaik, 1981).

The important constituents of the substrate that influence

the yield are cellulose, lignin, carbon' and nitrogen.

Zadrazil (1982) observed that cellulose and lignin content

of the substrate have direct impact on growth and development of

these mushrooms.

Bano and Nagaraja (1976) reported that Pleurotus species

utilise free sugars as long as they are available, thereafter

cellulose is the main source of carbon for fructification. They

secrete cellulolytic enzymes which leads to saccharification and

most of the sugars are used for growth and metabolism, while the

12

rest are left behind in spent straw; though Pleurotus species are

known to metabolize and degrade lignin, they colonize fast over

the substrate having low lignin content.

Sivaprakasam (1986) has found out that yield of oyster

mushrooms is positively correlated to cellulose content and

cellulose-lignin ratio. Cellulose rich organic substrates have

been reported to be good substrates for mushroom cultivation as

they enhance cellulase enzyme production which is positively

correlated to the yield; substrates with high lignin content were

found to affect the activity of cellulases and hence yield was

reported to have negative correlation to lignin content. C:L

ratio was found to be one of the important characters that will

influence the growth and yield performance of oyster mushrooms.

C:L ratio of 2:1, 2:1 to 4:1 and 4:1 alone were recorded to be

beneficial in oyster mushroom cultivation (Sivaprakasam, 1986;

Bisaria et al_. , 1987; Nandi, 1989; Desai et al . , 1991 and

Nallathambi, 1991) .

Bioefficiency was found to be influenced by the carbon,

nitrogen content of the substrates (Moorthy, 1991).

Rajaratham and Bano (1987) reported that yield of oyster

mushrooms would be maximum when the C:N ratio of the substrate is

13

61. Lopez and Hepperly (1987) observed that C:N ratio of about

60:1 could stimulate growth and yield of these mushrooms. Desai

and Shetty (1991) have found out that carbon, nitrogen ratio of

65,40 : 1 might be attributed to the high per centage of

biological efficiency of P.saior-caiu of 130.28, in paddy straw.

Overall reduction in carbon content of substrates, due to

its utilization in the growth and yield of oyster mushrooms was

observed (Bano, 1970; Bisaria et al., 1987).

Cultivation in relation to physical factors: Besides this,

physical factors such as temperature, humidity, light and oxygen

are associated with oyster mushroom cultivation.

Most of the oyster mushroom species are found to grow well

in a temperature range of 20° to 30° c. A fairly wide range of

temperature viz., 20° to 30° c had been advocated by several

workers for spawn run and 22° to 25° c for optimum

fructification. Humidity range of 75 to 85 per centage was found

to influence the mycelial, fruit body formation.

As diffused light promotes fruiting in oyster mushrooms, it

is advised to pass diffused light during cropping. Under

conditions of inadequate aeration and enrichment of carbon-di­

oxide in the atmosphere, combined with lack of sufficient

14

illumination, fruiting is abnormal and the fruit bodies developed

are long and slender (Jandaik, 1976; Sivaprakasam et al. , 1986;

and Marimuthu et al., 1992) .

Cultivation Methods

Growth and yield of mushroom are influenced by the

pretreatment of substrate, usage of polybags, utilization of

spawn in terms of quality and quantity.

Soaking of the bits of substrates to have a moisture content

of 70 to 75 per cent was recommended for higher yield (Bano et

al., 1987; Mohanan and Moorthy, 1991) .

Sterilization of substrate by boiling ,steam pasteurization

at 80° c for 2 hours and chemical treatment were advocated for

successful cultivation of oyster mushroom without contamination

(Bano et al., 1986) .

Most effective method of substrate sterilization by steeping

five Kilograms of chopped substrate in 50 litres of water with 75

ppm bavistin and 500 ppm formalin overnight; steam

pasteurization at 80° c for 2 hours was advocated (Vijay and

Sohi, 1987).

15

Usage of compact, closed polyethylene bag of 60 x 30 cm

size with two holes of 1 cm diameter was recommended for its easy

handling and better yield (Jandaik, 1976; Sivaprakasam, 1986;

Bano et al., 1987 and Marimuthu et al. , 1991).

Inoculation of substrate with grain spawn of first

generation at the rate of 4 per cent/Kg of wet paddy straw was

recommended for high yield (Zadrazil, 1978; Sivaprakasam and

Kandaswamy, 19 82).

Oyster mushroom cultivation on alternate substrates:

Bioconversion of different types of straws, leaves through oyster

mushroom cultivation was studied by many researchers. Straws and

leaves of cereals such as wheat, maize, bajra, sorghum and

pearlmillet were reported to be good substrates for oyster

mushroom cultivation either alone or in combination with paddy

straw.

Goswamy et al. (1987) reported that an average yield of

P. saior-caiu per Kg of paddy straw was 222 g while it was 229 g

in sorghum straw, 232 g in wheat straw and 200 g in bajra

straw. In combination with paddy straw, wheat straw recorded the

yield of 272 g in 3:1 combination, 254 g in 2:2 combination.

16

Bisaria et al_. (1987) recorded the yield efficiency of

P.saior-caiu in different straws in terms of fresh weight of

mushroom harvested using 100 g dry weight of the substrate.

Accordingly it was 111 g in wheat straw, 100 g in bajra straw,

108 g in jowar straw and 89 g in maize straw. In combination

with paddy straw in 1:1 ratio wheat straw could yield 120 g.

Calzada et al. (1987) observed that Pleurotus species could

perform best, results in wheat straw,in terms of mycelial growth

and production of fruit bodies.

Patil and Jadhav (1989) found out that wheat straw,maize

stalks and leaves,jowar stalks and leaves, bajra stalks and

leaves could be successfully employed for the cultivation of

P.sai or-caiu as it gives higher yield, besides being easily

available and cheap. In their further study (1991) it was

reported that P.saior-caiu could yield 900 g fresh mushroom per

Kilogram of dry wheat straw, 980 g in wheat straw-paddy straw

mixture, 705 g in pearlmillet stalks and leaves, 742 g in sorghum

stalks and leaves and 550 g in maize stalk.

Daniel et al. (1991) have reported that kudiraivali stalk,

sorghum stalk could yield 778.97 g, 860.50 g respectively per Kg

of dry substrate when they were mixed in equal combination with

paddy straw.

17

Savalgi and Savalgi (1991) have reported that P.sajor-caju

could give a total yield of 464 g/kg of dry wheat straw while

P.florida could yield 470 g/kg of dry wheat straw. Similarly in

jowar stalks, the yield of P. saior-caiu was 186 g; in P.florida

it was 202 g/kg of substrate.

Sharma and Jandaik (1991) observed the higher bioefficiency

of 80.66 percentage in P.florida grown on wheat straw.

Sivaprakasam and Kandaswamy (1981) experimented the cultivation

of P.saior-caiu using Delonix flowers and reported an appreciable

amount of yield.

Balasubramanya (1981) observed the yield of 500 g of fresh

mushroom of P.sajor-caju per kg of cotton stalk. Bisaria et al.

(1987) cultivated P. saior-caiu on cluster bean straws,, mango

leaves, banana leaves and reported the yield of 108 g; 61 g; 125

g of fresh mushroom per 100 g of dry substrate respectively.

Madan et al. ( 1987) experimented the leaves of Morns alba

and Ricinus communis for the cultivation of P.saior-caiu and

reported that the yield obtained from Morus alba was comparable

to the yield obtained from paddy straw. The biological

efficiency of M̂ _ alba was found to be 90 per cent and of

R.communis was 66.60 per cent.

18

Kala valli and Daniel (1988) reported that Pleurotus sajor-

caju could yield 386 of fresh mushroom in 500 g of straw paper

substrate, 228 g in straw-groundnut shell substrate. Effective

utilization of groundnut shell with paddy straw for this

cultivation P.saior-caiu and P.florida was reported by Savalgi

and Savalgi, (1991); Khander et al. , (1991); Patil and Yadhav,

(1991) conducted experiments of P. sai or-caiu cultivation on

coconut leaves, banana leaves, grass, green gram stalks and

leaves, blackgram stalks and leaves, soybean stalks and leaves,

sunflower stalk and leaves, sugarcane trash. They recorded the

bioefficiency of 58.3, 76.5, 63.7, 73.0, 78.0, 48.0 and 30.5

per cent respectively in the above substrate. Utilization of areca

leaf for cultivation of oyster mushroom was studied by Mohan and

Moorthy (1991). Singh and Singh (1991) reported the highest

yield of 729g fresh mushroom from a kg of soybean straw.

Agrobased industrial products such as coir waste, wood

shavings, willow dust, rubber wood processing wastes were

experimented- for recycling through oyster mushroom cultivation.

(Sivaprakasam and Kanadsamy, 1981; Balasubramanya, 1988;

Kothandaraman et al., 1991). Utilization of bagasse in P.saior-

caju cultivation was reported with the yield of 97 g fresh

mushroom (Bisaria et al., 1987); 71 g fresh mushroom (Azizi et

19

al. , 1990) and 75 g fresh mushroom per 100 g dry substrate (Rao,

1990). Coffee pulp which causes environmental pollution could be

effectively 'used for the cultivation of oyster mushroom with a

bioef f iciency of 175.8 per cent in P. f lorida, 128.12 per cent in

P.saior-caiu (Carrera, 1987; Calzada et al., 1987).

Pandey and Tewari (1991) evaluated the suitability of tea

waste and coffee pulp with different ratios of paddy straw for

the cultivation of P.florida and reported that there was

significant increase in the yield with the decreasing ratios of

tea, coffee waste. Juice extracted from cashew apple waste could

be effectively used for the cultivation of P.florida (Rao, 1991).

Oil palm mesocorp waste has a maximum conversion of 58.4 per cent

with P.florida, 55.7 per cent with P.sajor caiu and with 49.7 per

cent with P.citronopileatus (Babu and Nair, 1991).

Cultivation of P.florida, and P.saior-caiu was found to be

successful on cotton waste, maize cobs,sunflower husk (Savalgi

and Savalgi, 1991) Spent straw after harvesting mushroom can

also be effectively used for oyster mushroom cultivation

(Sivaprakasam and Kandaswamy, 1971; Sharma et. al.. , 1991).

Cultivation of oyster mushroom on leaves and stems of water

hyacinth with a bioefficiency range of 41.6 to 170.7 per cent was

also reported (Chocooj et al., 1993).

20

Oyster mushroom cultivation growth and yield study: Growth

study of oyster mushroom in terms of days taken for 50 per cent

mycelial run, 100 per cent mycelial run, budding and total crop

period was advocated by many workers; similarly yield study was

carried out from the mushroom harvested in each flush, maximum

size and weight of the individual mushroom harvested in a bed,

total yield in a bed and biological efficiency (Baskaran et. al. ,

1978; Bano et al., 1987; Vijay and Sohi, 1987 and Marimuthu et

al., 1991) .

Growth in terms of complete ramification of mycelium in

oyster mushrooms was reported to be within 12-20 days and

interflush period ranges from 5-13 days (Jandaik, 1976; Bano et

al-/ 1982; Khader, 1988)

Yield of oyster mushroom varieties was found to be 60

per cent of the net yield in first flush. (Bano et al. , 1982;

1987) . It was also reported that the yield of Pleurotus mushrooms

was found to respond to the climatic conditions (Bano, 1982).

Sivaprakasam et al. (1986) observed- that P.citrinopileatus

could yield 414 g per 500 g of bed while it was 360 g per 500 g

of bed in P.saior-caiu. Pandey (1991) reported the bioeffciency

of 63.4 per cent of P.saior-caiu using paddy straw. Marimuthu et

21

al. (1991) reported the yield of P. saior-caju as 346 g per bed,

P. citrinopileatus as 350 g per bed, P. f lorida as 316 g per bed

and P. sapidus as 297 g per bed of 500 g paddy straw.

Nallathambi (1991) reported the yield of 422.50 g per 500 g of

paddy straw with P.citrinopileatus, 361.27 g with P.sajor-caju,

322.50 g with P.sapidus and 351.25 g with P.florida.

Organic Amendments

Influence of carbon and nitrogen supplements to paddy straw

substrate was studied by various researchers.

Rajaratham and Bano (1987) reported that addition of

sterilized pulse and cereal grain powders at the rate of 50

g/kg"1 dry substrate to the substrate increase the yield of

oyster mushrooms.

Organic carbon sources such as tapioca starch, oatmeal and

nitrogen sources like redgram, horsegram powder and groundnut

cake were reported to increase the yield in oyster mushroom

(Rangaswamy et al., 1975, Kalavalli et al., 1991)

Compared to inorganic sources such as potassium nitrate,

ammonium tartarate, Plerotus species utilize organic nitrogen in

a better way and utilization of carbon source for the mycelial

22

build up was maximum in the presence of best suitable organic

nitrogen source (Khanna and Garcha, 1982)

Gunasegaran et al. (1987) reported the significant increase

in the yield of Pleurotus species when supplemented with organic

additives like rice bran,palm kernel cake, corn meal, coconut

cake and tobacco dust. Supplementation of substrate with

nitrogenous sources with cotton seed, soybean flour and alfalfa

meal also was found to influence the yield of oyster mushrooms

(Royse and Bahler, 1988; Mohmoud and Kattan, 1989).

Kannan and Oblisamy (1990) reported that addition of carbon

source would stimulate the ligninolytic activity of lignin

degrading basidiomycetes.

Rajarathnam et aJL. (1979) reported that cellulose is

actively utilized during mycelial growth and hence the content of

cellulose and carbon reduces after harvest; Pleurotus species

use more nitrogen during fruitbody formation and a proper supply

of nitrogen source to the substrate stage could contribute to the

increase in the yield.

Nutritive value and delicacy of oyster mushrooms

Mushroom have been equated to chicken for vegetarians for

23

their nutritive value.

Jandaik and Kapoor (1975) found out that P.sajor-caju has

protein content of 47.93 per cent and fat content of 2.26 per

cent on dry weight basis. Chang et al. (1981) reported that

there is variation in the proximate composition with variation in

substrate. Mushrooms grown on paddy straw has the lowest crude

protein of 26.6 per cent while it was 30.2 per cent in cotton

straw, 30.4 per cent in cotton straw mixed with paddy straw.

Chang and Hayes (1982) observed that oyster mushrooms have

the moisture content of 94.7 per cent, digestible protein of 21.6

per cent and fat of 7.2 per cent, total carbohydrate of 60.5 per

cent and energy value of 351 K cals. Haque and Chakrabarthy

(19 82) reported that mushrooms are gaining importance in view of

their pleasing flavour,adequate protein with a high digestibility

co-efficient of 87 per cent.

Stanton (1984) observed that compared to most of the

vegetables, mushrooms supply a slightly higher percentage of

protein; they contain a small amount of complex carbohydrates

than most vegetables with 3.8 g in a 100 g serving. They supply

many of the nutrients that are needed for good health. They have

24

low fat content which is a boon to weight conscious people

desiring less fat and more protein in their intake.

Sivaprakasam (1987) has noted that mushrooms are recognised

universally as food crop for its dietary value and also as table

delicacy. They have protein content of 26.72 to 28.47 per cent

and crude fat of 3.5 to 3.6 per cent. Pandey (1991) observed

that dried oyster mushrooms have more protein (27.8 per cent) than

kidney bean (21.3 per cent), lentil (24.7 per cent) dried peas

(24.2 per cent) cabbage (11 per cent) and roasted peanut (26.2

per cent).

Marimuthu et al. (1991) assessed the nutritive value of

oyster mushroom and found out that they have the moisture content

of 89.80 per cent, protein of 29 per cent , fat of 3.60 per cent,

carbohydrate of 53.0 per cent, ash value of 10 per cent and

energy value of 339 kilo calories; hence considered good food for

patients with diabetics and blood pressure.

Bahl (1991) reported that protein malnutrition in India

can be solved to some extent by the mushrooms which are

recognised by FAO (1977) as food contributing to the protein

nutrition of the countries depending largely on cereals and

pointed out that mushrooms digestibility is as well comparable to

pulses.

25

Nutritive value varies with varieties of oyster mushrooms

(Benjamin and Anuradha, 1991). According to their report,

moisture content, protein and ash content of fresh mushroom of

Pleurotus saior-caiu were 91.20 per cent, 2.20 per cent, 0.55 per

cent respectively while they were 90.60 per cent,2.02 per cent

and 0.63 per cent respectively in P.citrinopileatus.

The delicacy of these oyster mushrooms was assessed by

sensory evaluation. Bano (197 6) evaluated mushrooms based on

their colour, texture and flavour. Dessai e_t a_l. (1991)

evaluated the above aspects of oyster mushrooms employing a panel

of five judges with the score card of colour, texture, taste,

flavour and appreciation percentage and found out that P.sajor-

caiu scored less mark than P.citrinopileatus and P.florida for

its colour, texture. Khader and Padmavathy (1991) adopted the

method of sensory evaluation with the score card grades

comprising the phenomena such as appearance, colour, flavour,

taste, texture and overall acceptability.

Recycling of spent substrate

The spent substrate after the cultivation of mushroom was

found to be in the degraded form and offer a spectrum of

26

potential application as a garden manure (Bano, 19 7 6)v;-u,

During decomposition of straw-cellulose-lignin complex by

Pleurotus species under controlled conditions, the substrate

could develop fruit bodies which is 10 per cent of the original

straw. But 50 per cent of the substrate will be liberated as

carbon-di-oxide and about 20 per cent as water and the rest of 20

per cent of the original weight remains in the substratum

(Zadrazil, 1978). He also reported that spent substrates have

the decomposed substratum where organic, inorganic nutrients are

concentrated and are in an easily soluble and insoluble form. As

they have cellulolytic enzymes, the residual substrate can serve

as a basis for composting and can be added as organic manure

after composting.

Chang e_t ai. (1981) observed that application of spent

compost consisting of degraded cellulose and lignin, will improve

the soil condition. In addition it would provide a balanced

nitrogen and carbon source for microbial growth; the spent

compost will form the fine black material namely humus which

maintains the structure of the soil with good aeration and water

holding capacity. It can be used after two to three months of

further decomposition as a garden manure to grow vegetables.

27

Mariakulandai and Veluchamy (1981) reported that the green

leaf manures are useful, as their addition improves organic

matter, water holding capacity of the soil and also in enrichment

of soil with nitrogen and other nutrients. Leaves of Glyricidia

maculata, Ipomea cornea, Tephrosia purpurea. Leucaena

leucocephala and Sesbania speciosa are being used in India for

green manuring (Rao, 1985).

Fungi like Pleurotus species are known for degradation of

plant material (Bisaria et al. , 1983) . Lohr et al. (1984)

observed that the spent substrate in soilless media could

influence the yield and quality of transplant of different

crops. Wang et al. (1984) reported the spent substrate compost

as an amendment for growing vegetables. Bahl and Jahuri (1987)

reported that spent substrate is a carrier material for bacterial

inoculants like Rhizobium and Azotobactor which add fertility to

the soil by their nitrogen fixing ability.

Mani and Marimuthu (1992) observed that P.sajor-caju could

effectively degrade coir-pith waste and the utilisation of

decomposed coir pith as organic manure to grow different crops

was also recorded by them. The rate of decomposition of plant

residues by the fungi was reported to be influenced by the

28

substrate quality in terms of carbon and nitrogen. Besides this,

addition of leafy manure play important role in composting by

their biomass activity and nutrient availability (Savoie et al.,

1992) .

Cost Economy - Emphasis on Extension

Based on the studies of cost economy of oyster mushroom

production, necessity for extension of this technology to uplift

the economy of rural population was assessed.

Prakash and Tejaswini (1991) reported that cost of

production per kilogram of oyster mushroom was only Rs.10.75/-

and hence could be cultivated at various scales. Nagarkar (1991)

emphasised that inspite of congenial climatic condition for

growing oyster mushroom in various parts of India, its

cultivation could not be estabilised due mainly to less practical

involvement of research institutions in setting up demonstration

at different sites of rural and urban locations.

Suharban and Nair (1991) have revealed in their study that

growing mushrooms can go a long way in the efficient utilization

of agricultural waste and extension of this technology to the

villages could motivate unemployed youth to adopt it as an

occupation. Joseph et al. (1991) emphasised the extension of

this technology to villages which can give employment to educated

29

youth and people engaged in non-agricultural pursuits. Kalavalli

et al. (1993) emphasised the extension of this technology, as its

simplicity could lead the trained women to take up this venture

to improve their socio-economic status. Sharma (1993) reported

that extension of this technology could augment the income of the

grower as the cost of production is between Rs. 8 to 15 per kg and

the sale price is about Rs.20 to 25 per kg of fresh mushroom at

production centres.

30

PROFILE OF THE STUDY AREA

The study area namely, Dindigul Anna District of Tamil Nadu,

India, is located between 10° 05v and 10° 9N north latitude and

77° 30v and 78° 20x east longitude with an approximate area of

6070.26 sg. km. Dindigul, the headquarter city, has the network

of interdistrict road connecting Coimbatore - Periyar,

Tiruchirappalli, Madurai and Pasumpon Muthuramalingam Districts.

This district has extensive hilly and rocky areas with

undulating plain. Palani hills forming northern spur of the

western Ghats comprise, three valleys, several peaks viz.,

Perumal hill, Vandaravu hill, Thandikudi hill, Virupakshi hill

etc. On the eastern side, Sirumalais, Alagar malais and Natham

and Ailur hills are seen.

Climate, Temperature and Rainfall

Semi arid tropical monsoon type of climate prevails in

plains. However upper plains recorded low temperature and heavy

rainfall.

In the plains, maximum and minimum atmospheric temperature

are 37.5° and 19.7° c and in the hill stations 20.6° and 7.7° c

respectively. Heat becomes intense in April and May.

The annual rainfall is about 836 mm excluding Kodaikanal.

North east monsoon is the principal monsoon.

Vegetation

The natural vegetation is rich and varied; about 700 species

accounting for 50-80 per cent of the flora of whole Indian

Peninsula have been identified in this district.

Agriculture and Land Use

About 45 per cent of the area is put under cultivation. Dry

farming is predominant. Paddy is the principal crop (37 per cent)

followed by oil seeds (23 per cent) , fruits and vegetables (24

per cent) . Sorghum is the major irrigated crop (30 per cent)

followed by oil seeds (18 per cent) and paddy (11 per cent).

Socio-Economic Indicators

In the 14 blocks and 24 town panchayats of this district,

density of the rural population per sq.km. is 205, urban is 80.

Number of females per 1000 males is 980/ average size of rural

household is 4.9 and urban 4.5; percentage of workers to total

population from rural areas is 31.5, urban areas is 2.4;

percentage of agricultural labourers to total agricultural

workers is 39.7.

32