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close this bookBiodiversity in the Western Ghats: An Information Kit (IIRR, 1994, 224 p.)
close this folder5. Agriculture
View the document5.1 Rice diversity and conservation in the Konkan
View the document5.2 Conservation of traditional vegetables in the backyard
View the document5.3 Genetic diversity in mango and cashew
View the document5.4 Floriculture and arboriculture
View the document5.5 Enriched biodiversity by plant introductions
View the document5.6 Impact of introduced plants
View the document5.7 Effects of pesticides on biodiversity
View the document5.8 Khazan (saline) lands

5.1 Rice diversity and conservation in the Konkan

The spread of high-yielding varieties means that in 15 years just 10 varieties may cover as much as 75% of the total rice area. The country's rich genetic diversity in rice is being destroyed.

Some 50,000 rice varieties are grown in India. This is a very rich source of genetic variety, of great value for plant breeding.

But government officials and industry have promoted only a very few "modern" rice varieties. The spread of high-yielding varieties means that in 15 years just 10 varieties may cover as much as 75% of the total rice area. The country's rich genetic diversity in rice is being destroyed.

This diversity is a result of centuries of selection by farmers, adaptation to various environments, breeding with wild relatives and local varieties, and the evolutionary process over centuries.

In the Konkan region of Maharashtra, hundreds of indigenous cultivars were cultivated. The sophistication and stability of rice farming can be judged from the fact that even the smallest tribal farmer, with a land holding of less than a hectare, had six to eight varieties of traditional seeds suited to local microclimates and soils.

But farmers are replacing these hundreds of cultivars with just six or seven high-yielding varieties. This is reducing the genetic background of rice varieties over wide areas in the Konkan. This genetic erosion poses a danger to the long term food security of the region.


Now efforts are on to conserve these valuable rice varieties. ADS, the Academy of Development Sciences in Karjat is painstakingly collecting samples of rice varieties which have been grown in this country over generations.

While many of the old varieties have disappeared, many still survive. Some "orthodox" and "stubborn" farmers still stick to planting traditional varieties of paddy, Around 300-400 traditional varieties of rice are currently grown in the Konkan, according to an ADS study.

ADS has a three-acre field gene bank and seeks to encourage the use of traditional seeds by farmers. ADS workers meet farmers and seek their help to identify farmers who still have traditional rice-varieties in their fields. They ask for a few panicles of the rice, which are then taken back and replicated at ADS. They can then be once again promoted among farmers for cultivation.

A rice field

Amazing diversity

Rice has amazing diversity. In colour alone, the grain varies from white to red, brown and black. This diversity is a result of selection by farmers. adaptation to various environments, breeding with wild relatives and local varieties, and the evolutionary process over centuries. Rice of different types can be differentiated one from another on the basis of various characters.

For instance, there is the yield and duration of the crop. Rice varieties also vary in terms of their ability to withstand excess or shortage of water, their ability to grow in acid, alkaline or saline conditions, and their resistance to pests and diseases.

Rice varieties also differ from one another in terms of habitat; plant height; leaf shape, size and colour; ligule and auricle; grain shape, size and colour; features of the panicle; sterile/fertile lemma; and the awn.

Dangers of uniformity

Going in for genetic uniformity is fraught with dangers, warns ADS.

Industrial monocultural agriculture and its high-yielding varieties favour genetic uniformity. Vast areas are planted to a single variety, requiring expensive inputs such as irrigation, chemical fertilizers and pesticides to maximize production. In the process, not only traditional crop varieties, but long-established farming ecosystems are obliterated.

Genetic uniformity invites disaster because it makes a crop vulnerable to attack. A pest or disease that strikes one plant can spread quickly throughout the crop. In some regions, the risk is considerable: Some 62% of the rice varieties in Bangladesh, 74% in Indonesia and 75% in Sri Lanka are derived from one maternal plant.

Farming the Konkan

Agriculture in the Konkan-the narrow strip of land along the Bombay-Goa belt-is mainly rainfed. Lands in the Maharashtra part of this region are divided into Garva lands (with good water), Neem-Garva lands (with medium water holdings), and Halva lands (with poor soil).

Indigenous vs modern rices

Modern rice varieties have high yields, but they lose to indigenous varieties when it comes to other characteristics.

Indigenous varieties

Modern varieties

Ability to withstand water stress

+ +


Ability to withstand adverse soil conditions

+ +


Resistance to pests and disease

+ +


Conservation of gene banks

+ +


Cost of inputs


+ + +

Genetic uniformity invites disaster because it makes a crop vulnerable to attack.

5.2 Conservation of traditional vegetables in the backyard

You can make a big contribution to conserving the biodiversity of vegetables in the Western Ghats region in Goal

· Grow traditional vegetables in your backyard in your spare time.

· Conserve these plants to assure their survival for generations to come.

· Grow them using organic techniques so as not to alter the original characteristics of the variety.

This list is not exhaustive.

Start conserving biodiversity. Your backyard is your first environment!

Okra, Ladies' finger (Hibiscus esculentus)

Sweet potato (Ipomeea batatas)

Ginger (Zingiber officinalis)

Onion (Allium cepa)

Traditional vegetables in Goa

Local/Common name

Scientific name

Part used as vegetables

Additional uses and features

Ecological Status

Tambdi bhaji

Amaranthus gangeticus

Entire plant

Rich in iron, cellulose, fibre


Shepu, Dill

Anethum sowa

Entire plant

Treats stomach ailments


Konkan dhudi, Bottle gourd

Lagenaria vulgaris


Large size and soft texture medicinal value


Vaingan, Brinjal, Eggplant

Solanum melongena


Round purple (annual)


Long green (perennial)

Very rare

Long greenish purple (perennial)


Padwal, Snake gourd, Podollim

Tricosanthes anguina


Agshi variety (1m long, 8cm across)

Getting rare

Common variety(75cm long, 4-5cm across)


Gonsallim, Ridge gourd, Angled loofah

Luffa acutangula


Large and long

Very common

Mullo, Radish

Raphanus sativus

Entire plant

Taleigao variety of medicinal value

Seed not available, variety conserved by certain growers

Moshing, Drumstick, Horse-

Moringa oleifera, radish tree

Fruit, leaves flowers

Rich in iron



Cucumis sativus


Long variety (usually eatern when mature)


Smaller variety(eaternwhen tender)


Tendli, Gerkin

Coccinia indica


Small variety

Not very common

Large variety

Grown for market

Red sorrel, Roselle

Hibiscus sabdariffa

Okra, Bhendi, Lady's finger

Hibiscus esculentus


Satpani (large) early fruiting

Seed not easily available



Chilli, Mirsang

Capsicum annuum


Canacona variety(kholchi)

More common in south Goa

Aidona variety(sweetish)


Portugali mirsang, Chilli

Capsicum frutescens


Very tiny, used for papads and pickles(very pungent)


Red pumpkin

Cucurbita maxima

Fruit, leaves, flower

Large and long (oval shaped) Round (of medicinal value)

Endangered Common

Ash gourd, Wax gourd, Kunvallo

Benincasa hispida


Used for sweets


Karela, Bitter gourd

Momordica charantia


Large (Ponda variety)

Seed not available to others, conserved by grower



Golchi bhaji, Parslane

Portulaca oleracea

Entire plant

Medicine for diabetes


Valchi bhaji/Climbing spinach

Basella alba

Leaves, tender shoots

Rich in iron, vitamin A

Very common


Zanthoxylum shetsa


Used as a spice



Averrhoa bilimbi


As a souring agent


Matti Gonsallim, sponge gourd

Luffa cylindrica


Fibre used as sponge/scrubber


Suran, elephant yam

Amorphophallus campanulatus


Not to be mistaken in edible variety


Zad conong

Tuber, bulbil

Smooth skin, small size


Tero, Arum

Colocasia esculenta


Green variety



Garcinia indica


Of medicinal value, Used as a souring agent



Curcuma longa

Rhizome, leaves

Used as a spice, of medicinal value, leaves used for their flavour

Very common


Zingiber officinale


Of medicinal value, used as a spice



Allium cepa


As a seasoning agent, of medicinal value

Local variety endangered


Piper nigrum


Used as spice, of medicinal value

Local variety high yielding endangered


Vigna cylindrica

Pod, seed

Of medicinal value

Very common

Alsando, Lentil

Lens esculenta

Pod, seed, leave




Vigna unguiculata


White+ brown


Moog, Mung, Green gram

Phaseolus aureus


Nutritive value

Local variety extinct

Anvre, Hyacinth bean

Dolichos lablab


Large variety





Phaseolus sp.


Resembles white pepper


Bamboo, Kill

Bambusa bambos

tender shoots

Maroon shoots


Nachni, Finger millet

Eleusine coracana


Rich in iron, of medicinal value


Kudukki Bhaji

Amaranthus spinosa


Rich in iron




Rhizome, leaves

Rich in protein


Kata konong,

Dioscora esculenta


Nutritive value


Potato yam


Dioscora esculenta


Nutritive value


Sweet potato

Ipomoea batatas


Food value


Nir ponos, Bread fruit

Artocarpus incisa


Nutritive value


Taikulo, Foetid Cassia

Cassia tore

Entire tender plant or leaves

Rich in iron

Common, hardly used

Tidki/Cluster beans, Gawar

Cyamopsis tetragonoloba


High fibre content



Tuber, bulbil

Nutritive value (pinkish white variety)


Kiraitem, Chirata

Swertia chirata

Entire plant

As a dewormer, for treating diabetes, malaria





As a souring agent


Sword bean, coto vad

Canavalia ensiformis


Long and broad


Prepared by Francis Borges

5.3 Genetic diversity in mango and cashew

Though they look very different, mango and cashew are relatives. Both belong to the botanical family Anacardiaceae.

Both are economically very important in all the Western Ghat states from Gujarat to Kerala.

Though they are related, mango and cashew come from opposite ends of the globe. Mango is native to Assam in the Indo-Malayan realm, which stretches from Pakistan to western Indonesia. Cashew originates from Brazil in the western hemisphere.

But both have become naturalized in the Western Ghats, and most people in the region think of them as natives. The two tree species and their produce form part of the religion and culture as well as the diet of local people.



Cashew (Anacardium occidentale)

Cashew seeds were brought to India by the Portuguese in the 16th century to prevent soil erosion and mud-slides during the heavy monsoon rains. It was only in 1926 that local people discovered that the kernel was edible.

The cashew has been naturalized in the Western Ghats to such an extent that scientists refer to centuries-old varieties as "indigenous". These varieties have adapted to local soil, climatic and biotic conditions. Natural selection has ensured that the best adapted varieties could survive and multiply.

Cashew kernels are rich in protein (21%) and fat (47%). They contain 22% carbohydrate. They are high in iron (5 mg/100 g), vitamin B1 (630 mg/100 g) and B2 (190 mg/100 g), but low in vitamin A (100 I.U./100 g).

Cashew kernels, or "nuts", are a much sought-after and healthy snack food. The germinating nuts, called godavlim, can also be eaten.

In the northern Western Ghats, cashew juice is drunk fresh or is fermented into fenny, wines and vinegar.

Cashew nut shell liquid is used to treat wood against termites, and is used to make paints, varnishes, and other chemicals.

A major problem in cashew cultivation is fungal pink disease. The most serious pest is the tea mosquito bug, which can cause complete crop loss. The stem boring beetle, though less important economically, can kill the trees.


Attempts to boost cashew production have meant that a few high-yielding varieties are now multiplied by the million. They are sold to farmers with government subsidies. These varieties have low tolerance to the tea mosquito bug. Planting a single variety exposes entire plantations to being wiped out by this or other pests.

The National Research Centre for Cashew, at Puttur in the central Western Ghats, has collected more than 300 varieties of cashew. Universities and research stations maintain plants in Vengurla (Maharashtra, 161 varieties), Chintamani (Karnataka, 172 varieties), and Madakkathara (Kerala, 115 varieties). Research stations at Ullal and Vittal (Karnataka) also have cashew collections.

Not a nut

Cashew "nuts" are not really nuts: botanically they are fruit because they contain a kernel and pericarp (an outer hard coating).
The cashew "apple" is not a fruit: it is a swollen fruit stalk.

Development of the cashew "nut" and "apple"

Mango (Mangifera indica)

India has more than 1000 named varieties of mango. Forty species of Mangifera are known, but only three are found wild in India: the cultivated Mangifera indica, and two others. In Goa, 77 varieties of mango have been reported.

Mango has five genomes (sets of chromosomes). This is unusual because most plants have an even number of genomes: two, four, six or eight. This complicates the breeding of new mango varieties.

Because seedlings are genetically different from the parent plants, true varieties can be maintained only through grafting.

Some varieties common in northern parts of the Western Ghats, such as Alphonso and Malcurada, have delicious fruits but bear fruit only every other year. Varieties further south produce fruit every year, but the fruit is of poorer quality. Plant breeders have crossed varieties from the north and south to get trees that produce good quality fruits every year. Some of these hybrids are Anmol, Ratna and Sindhu.

Popular mango varieties

- Early season Malcurada, Malgueso, Bemcurada, Pairi
- Mid-season Xavier, Colaco, Alphonso, Chimud, Udgo, Bispo, Secretina
- Late season Fernandina, Hilario, Monserata

Endangered or extinct varieties

Brindao, Mogri, Mirio, Don Filipe, Don Bernado

Mango fruit shapes

Mango fruit

Different mango varieties produce fruit of various sizes, taste and colour. They bear fruit at different times of the year, meaning that the mango season is getting longer. Some varieties are resistant to powdery mildew disease and pests such as mango hopper and fruit fly.

Mangoes are sweet because they contain a lot of sugar: between 10 and 18% of their weight. They are also high in vitamin C (25 to 175 mg/100 g) and vitamin A (0.8 to 13 mg/100 g).

Summer, from March to June, is mango season in the Western Ghats. Although it is a seasonal fruit, Indians eat a large number of mangoes: an average of 4 kg a year. They consume only 9 kg of bananas a year, even though bananas are available all year round.

The fruit can be eaten in many forms: fresh, canned, as juice or jam, sun-dried, or pickled in brine or spices.


A new technique of grafting the very young shoots of newly germinated seedlings has made it easier to propagate and conserve rare varieties. Universities and research institutes are establishing germplasm banks to conserve important varieties.


Mango trees symbolize goodness, and mango leaves are strung across doors on auspicious occasions.

Prepared by Miguel Braganza

Information kit produced by
WWF-India, Goa division and the
International Institute of Rural

5.4 Floriculture and arboriculture

The warm, humid climate of the Western Ghats is conducive to plant growth all year round. A vast collection of grasses, herbs, shrubs and trees grow in the varied ecosystems of the region. Some have been commercially used-even over-exploited. Others have their commercial or ornamental value yet to be discovered.

When a plant species is domesticated and used, its economic value ensures that it is multiplied and preserved. On the other hand, this can lead to a narrowing of the genetic resource as only those varieties or species of economic value are conserved.


The Western Ghats are home to 250 orchid species, of which 100 are endemic. There are 71 species of Impatiens, some species of palms, 150 species of grasses and other plants of ornamental value. A host of introduced plant species, including Hibiscus, Lantana and Capsicum have naturalized in this region.

The government focuses attention on commercial floriculture by identifying centers where particular plants can thrive (such as orchids in Kerala), and promotes the industry through generous subsidies. It discourages the offering of bouquets and garlands by encouraging event organizers to offer a potted plant to guests. Alternatively, the guest can plant a tree at the event site.

Worth 1000 words...

Flowering plants beautify our houses and add colour and fragrance to our cities. They hide ugly spots and protect homes from dust and noise. They absorb carbon dioxide and release oxygen.

Flowers adorn women's hair and decorate pictures of gods, saints, national leaders and deceased loved ones. Garlands are exchanged by the bride and groom in traditional Indian marriages, especially among Hindus. Flower scents are extracted for use when the flowers themselves are not available.

Flowers of a certain species or colour are associated with Hindu dieties. For instance, white flowers are offered to Shiva. At Mangueshi temple, only Zuyee flowers are offered at a special pools during the full-moon at the end of the rains.

Irrespective of religion, we offer bouquets on joyous occassions and wreaths at funerals. The age-old tradition of putting a token trowel of soil on the grave has been replaced by the placing of a flower.


Trees are original inhabitants of the Western Ghats. Native tree species are still abundant, though their numbers have decreased.

Coconut and cashew plantations are not a threat to native species. Acacia auriculiformis and A. mangium, introduced from Australia for planting on mining dumps, may become a threat to native species if they are not controlled.

Large-scale felling of teak and other timber species is not desirable in the Western Ghats. The region's steep slopes and heavy rainfall makes the soil prone to erosion. The traditional practice of selective felling of mature trees is a more suitable alternative.

Flowers in the economy

The jasmine group of Mogrem, Zuyee (J. sambac, J. officinale and J. auriculatum) combine beauty with fragrance. Jasmines are used to make aromatic jasmine oil used in cosmetics and soaps.


Cut flower growing is a booming business in India. Orchids, anthuriums, roses and chrysanthemums are grown for export of cut flowers.
Periwinkles are grown extensively for extraction of cancer-curing alkaloids.
Glorylily pods and roots are used in medicine.

Timber plantations

A number of companies are promoting monoculture teak and rosewood plantations in the Western Ghats. They promise high profits, but current levels of technology does not make such planting feasible or desirable. Block felling at a later date will result in soil erosion.

Timber plantations

Indigenous and exotic tree species in the Western Ghats




Runeala plum, jagam, jangma

Flacourtia jagomas

Fruits relished by children. Eaten after softening between the palms of the hands.

Adam's fruit, adao, manilphal

Mimusops kauki

Fruits are eaten. Seedlings used as rootstocks for sapota grafts. Wood is used for furniture.

Elengi, bakul, vonvlam

Mimusops elengi

Creamy-brown scented flowers are used as hair adornment and to mask body odour. Fruits are edible.

Java plum, jamun, jambool

Syzyzium cumin

Fruit is edible and used in control of diabetes. Excellent for wines, liquor. Wood is good timber.

Guava, pew, amrud

Psidium guajava

Fruit is the tropical apple, rich in vitamin C and pectin. Made into jellies. Wood for walking sticks.

Cashew, kaju

Anacardium occidentale

Kernel is excellent snack, Shell liquid used for termite control, "apples" used for alcoholic drink.

Mango, ambo, am*

Mangifera indica

Excellent table fruit, trunk is used to make dug- out boats. Leaves used in religious ceremonies.

Hog plum, ambado

Spondias mangifera

Immature fruit cooked at Divali, made into pickle in brine or spices. Ripe fruit relished.

Bengal almod, badam*

Terminalia catappa

Fruit pulp and kernel edible. Leaves become red in cold weather, beautiful tree for large garden.

Marat, marti*

Terminalia creneleta

High class timber, adopted as the State Tree of Goa.


Terminalia paniculata

High class timber obtained from its trunk.

Benteak, nano, nanan*

Laigestroemia lanceolata

Wood used in furniture and ship-building. Bark is used for tanning leather.

Indian teak, sailo, jati*

Tectona grandis

Most commonly used wood for furniture, rafters, railway sleepers.

Jack, pangs, borkoi*

Artocarpus integrifolia

Multiple fruit relished, rich in vitamins A and C, Wood used for furniture. used as cattle feed.

White teak, shewan*

Gmelina arborea

Wood used in mine-shafts and or handles. Fruit is eaten by some birds and animals.

* indigenous to India

Flowering trees, shrubs and creepers

Common name

Scientific name

Local name

Parts used




Crossandra udulifolia

Abolim, priyadarsha


Festivals, weddings, Lent season processions, traditional folk dances(Dekni, Fugdi and Mando)

Jasmines (Indigenous)

Jasminum sp.

Mogrim, zuye, zayee

Flowers, scent

Zayeechi Poornima (full moon) festival


Catharanthus roseus

Perpet, sadaphuli

Flowers, leaves

Leukemia treatment. Normally grown in cemeteries as it requires little maintenance. Commercially cultivated.

Ixora (Exotic)

Ixora coccinea

Pitkol, pidkol

Flowers, stem

Wreaths, walking sticks.


Lantana camera



Flower beds. Used as mosquito replellant. Easily becomes a weed if seeds are allowed to germinate.

Paper chase(Exotic)


White bracts



Hibiscus rosasinensis

Doshin, dushwanti


Ornamental, shoe/heir blackener. As salad dressing, along with onions. White flowers used in Shiva temples.

Sickle senna(Indigenous)

Cassia tore

Thaikulo, taikulo

Leaves, seeds

Vegetable, ringworm cure, mordant, coffee substitute during economic crisis


Rosa sp.



Bouquets, rose water. "Gulkand" (a paste of rose petals and sugar) eaten with betel leaves and areca nut ("pan supari') on festive occassions.





Potted plant which flowers almost all year

(Patient Lucy)



Indian labernum(Exotic)

Cassia fistula


Flowers, leaves, pods

Ornamental, liver ailments, purgative(crushed pipe-Eke pod)


Michelia champaca

Champa, chamfo


Hair adornment, fragrant flowers, normally wrapped in banana leaf, often sold at bus stands.

Coral tree(Indigenous)

Erythrina indica


Flowers, leaves, whole tree

Ornamental, fodder (leaves), shade in coffee plantaions, support for pepper vines


Cycus bedami


Whole tree, leaves

Ornamental palm

Fishtail palm

Caryota urens

Billo mead

Whole tree, leaves

Ornamental, caryota leaves and fruit bunches used as decoration at feasts and weddings.



(Exotic) Polianthes sp.

Rajniganda, tuberose


Bouquets, garlands, scents. Flowers add fragrance to reception halls.

Marigold (Exotic)

Tagetes erecta



Garlands, anthelminthic, stomach upset(flower decorations), garlands at Desshera festivals and weddings

Glory lily(Indigenous)

Gloriosa superba


Flowers, fruits, roots

Ornamental, leprosy treatment

Ice-cream creeper (Exotic)

Antigonum leptopus




Rangoon creeper (Indigenous)

Quisqualis indica



Ornamental, flowers worn in hair

Prepared by Michael Braganza

5.5 Enriched biodiversity by plant introductions

Five hundred years ago, India had no potatoes, groundnuts, tomatoes or chilliest These important crops are relative newcomers to Indian fields and cuisine.

Ports on the west coast of India-Surat, Bombay, Dabhol, Goa, Honavar, Mangalore and Cochin-have played an important role in the import and dispersal of useful exotic plants. Before medieval times, Goa traded with the African coast, Egypt, the Persian Gulf and S.E. Asia.

Despite this, the agricultural resource base of India, especially of cash crops, was very limited before Vasco da Gama's discovery of the sea route to India in 1498. The subsequent arrival of the Portuguese, British, French and Dutch intensified battles to control the seaborne trade. The Moghul empire (1526-1857) granted liberal trade concessions to foreign powers. Intense trans-oceanic and maritime trade brought exotic species to Indian shores and diversified regional plant gene-pools.

The growing demand for novel crops (such as tobacco and pineapple) led to the establishment of experimental nurseries and plantations, mostly by missionaries. The novelty and utility of many exotic plant species brought a change in the agricultural economy, food habits and cultural practices of the Western Ghats and India as a whole. By the early 18th century, the cultivation of tobacco, chillies, chickoos, guavas, sitaphals, pineapples, oranges, cashews, papayas and breadfruit was established in South India.

India became one of the world's largest producers of some of the imported crops.

Biodiversity revolution

The natural dispersal of isolated plant species is not a major factor in the spread of cultivated plants from their native countries. Human action is thus the only significant way regional plant diversity is enriched. The intercontinental exchange in plant species in the last 500 years was thus a major event in world history.

Over history, isolated wild plant gene pools have been used for strategic reasons, to bring about a calculated shift in agricultural economies of colonized areas. For instance, the Portuguese took Indian and Southeast Asian spices to Brazil for cultivation; the British and Dutch brought rubber from Brazil to Malaya and Indonesia. Other plants brought as gifts for local elites later became popular, resulting in their widespread local cultivation. These crops are now very important in their new areas, often overshadowing their role in their original homes.

Major producer of exotic crops

In 1992, India produced:

· 480 million kg of tobacco
· 8 million tonnes of groundnuts
· 5 million tonnes of tapioca
· 0.5 million tonnes of chillies
· 15 million tonnes of white potatoes
· 1.3 million tonnes of sweet potatoes
· 1 million tonnes of pineapple
· 0.3 million tonnes of cashew nut
· 1 million tonnes of tomatoes, chickoos, pumpkins, etc.

Before 1498, none of these was found in India. Today, India is among the world's major producers of many of these crops.

Conservation of introduced, economically useful plants

· Survey, document and identify introduced species and their cultivars.
· Exchange information with authorities in regions with high diversity.
· Monitor the status of endangered species in their native places and share such data.
· Freely export healthy wild germplasms to their native places for reintroduction.
· Follow up reintroduced plants until the species is established and multiplies in its original habitat.

Intercontinental maritime trade routes linking India, SE Asia, Africa and S America were also routes for the exchange of plant germplasm. This enriched regional biodiversity and revolutionized cropping pattern and the agricultural economy of many parts of the world.

Exotic species in Goa

The Portuguese rulers of Goa catalyzed intercontinental plant genetic resource exchanges. Techniques of mango grafting were improved substantially by Portuguese missionaries in Goa, helping diversify mango cultivars. Over 20% of Goa's plants appear to have been introduced by the Portuguese between 1510 and 1961.

Exotic species in Goa

Pre-Vasco da Gama (before 1498)

Major crops were limited to rice, lentils, cotton, sugar cane, wheat, jowar and bajra.
The Indian menu had no chillies, potatoes, tomatoes, peanuts, pineapples, guavas, papayas, maize, custard apples or pumpkins.
None of these plants were family or tribal totems or mentioned in literature or used in rituals.

Post-Vasco da Gama (1498 onwards)

Tobacco and pineapples were favoured by Deccan sultans and Moghul emperors.
In the 16th century, chillies, cashew, peanuts, potatoes, pineapples, papayas and other crops were introduced.
Exotic species gradually enter the Indian menu and markets.

"Vavilov centres": areas of origin of most cultivated plants

Some economically useful plants species and their original home


Common name

Native of

Tagetes erecta

African marigold

Mexico (intro via Africa)

Ananas cosmosus



Acacia auriculiformis

Australian acacia, Bengali babool


Casuarina equisitifolia

Beefwood, shuru


Artocarpus indica



Brassica oleracea

Cabbage, kobi

Mediterranean Europe

Anacardium occidentale



Manikara achras



Lagerstroemia indica

Chinai mendi


Portulaca grandiflora

Chini gulab

South America

Theobroma cacao



Coffea arabica

Coffee, cafe


Coriandrum sativum

Coriander, kothmiri

Mediterranean Europe

Punica granatum



Terminalia catappa

Deshi badam


Hibiscus rosa-sinensis



Ricinus communis


Tropical Africa

Eucalyptus tereticornis

Eucalyptus, nilgiri


Quisqualis indica

Firangi chameli, rangoon creeper


Tagetes patula

French marigold

Mexico (intro via Africa)

Cercus pentagonus

Firangi, nivalkati


Kallanchoe pinnate


Tropical Africa







Delonix regia


Madagascar, Mauritius

Flacourtia inermis



Myristica fragrans

Jaiphal, nutmeg


Gardenia jasminoides



Ipomoea batatas

Kangi, sweet potato

Tropical America

Averrhoa carambola



Gossypium barbadense

Kidney cotton

Peru, Brazil

Syzygium aromaticum



Lens esculenta

Lentil, alsando

Mediterranean Europe

Litchi chinensis


South China

Hibiscus mutabilis



Syzygium malaccensis

Mallaca jamb


Annona muricata


West Indies

Acacia mangium

Mangium acacia


Capsicum spp.

Mirchi, mirsang

Haiti, Tropical America

Citrus sinensis

Mozambique orange, musambi


Opuntia elatior



Eupatorium triplinerve

Tropical America


Onion, kanda, Iruli


Carica papaya


West Indies &

papaya, pawpaw

Gulf of Mexico

Canavalia gladiata

Pandhri abai

West Indies

Psidium guajava

Per, Peru, guava


Citrus reticulate

Portugal/mandarin orange

China & Indochina

Arachis hypogaea



Cucurbita maxima

Pumpkin, dudhi, keddu


Annona reticulate


West Indies


Red oil palm,




West Africa


Saro, Mexican

Mexico (intro



via Africa)

Bixa orellana

Sendri rangmala


Chrysanthenum coronarium


China & Japan

Annona squamosa

Sitaphal, Ateria

Mexico (intro via Philippines)

Phaseolus caracalla

Snail plant


Phaseolus lunatus

Snail plant

South America

Phaseolus vulgaris

Snail plant

South America

Helianthus annus

Suryaphool, sunflower

Western U.S.A.

Borassus flabellifer


Tropical Africa

Hibiscus subdariffa

Tambdi ambadi

Tropical America

Manihot esculenta

Tapioca, cassava

Tropical Africa

Camelia sinensis

Tea, chai


Nicotiana tabacum

Tobacco, Tambakhu


Citrus maxima



Prepared by Mr. Nandkumar Kamat

5.6 Impact of introduced plants

Plants from all over the world have been brought to the Western Ghats and grown there. Some have vanished, while others have become naturalized and multiplied, either with or without active human intervention. Some have been beneficial, while others have become weeds or have had other serious consequences.


Chillies have substituted black pepper in trade, cultivation, research and culinary use. The colonial powers of the 16th century had sought exactly this when they discovered this easy-to-grow spice in South America.

Onions from Persia were used to keep slave labour healty while building the pyramids of Egypt. They have displaced vegetables during the winter cropping.


Coffee and tea are the products of plants introduced from Africa and China respectively. Large areas of virgin rainforests have been thinned down in Coorg and Wynad to grow these crops.

Revegetation programmes

Revegetation programmes have brought about the introduction of some many-seeded, quick-growing plant species suitable for adverse soil conditions and poor management practices. Two species of Acacia, many species and hybrids of eucalyptus and Casuarina equisitifolia have been brought from Australia for these projects. The high demand for wood pulp for the paper and rayon industries and for poles as construction props led to an exponential growth of areas under these species with little thought on their impact.

The Australian acacia's name has been indigenized within a decade of its introduction in social forestry programmes. It is called the "Bengal acacia" or "Bengali babool" so is confused with the native acacias called locally "babool" and "subabool".

Plants of the above three genera have been extensively grown along roadsides. They cause severe chest and bronchial sickness in many people, especially during pollen-shedding seasons.


Some introduced plants in the Western Ghats

- Spices
Chillies, onion, cloves, nutmeg, allspice, coriander

- Beverages
Tea, coffee, cocoa

- Fruits
Custard apple, pine apple, papaya, guava, chikoo, mango, iamun.

These three plant types shade the ground and their leaf-fall mats the ground below. Little or no undergrowth is present. In the high rainfall conditions of the Western Ghats, this results in soil erosion, poor rainwater percolation and low water table in the post-monsoon season. The high water-uptake efficiency of these xerophytic plants aggravates the water problem during summer.

The "leaf" of Australian acacia is a modified petiole (phyllode) while that of the casuarina is a modified branch (cladode). These and the true leaves of the eucalyptus do not decompose easily, suppressing insect and microbial activity and changing the soil characteristics. Casuarina has destroyed both the beauty and the sands of beaches which it was planted to protect against erosion.

Accidental introductions

Not all introductions are intentional. Eupatorium, Parthenium and Mexican Weed came along with American wheat. The blame for these weeds goes to PL480 aid and poor quarantine in the USA and India in the 1960s. These weeds first established near railway and shipyards handling the wheat and then spread to other areas. Eupatorium is a serious problem even in Goa's Cotigao Wildlife Sanctuary. It can cause immense damage to the plant, mushroom and animal diversity in this sanctuary. Lantana, Milkbush Euphorbias and some other plants have also become weeds in some areas.

Water Hyacinth

The Water Hyacinth has beautiful flowers. Fragments of the plant can regenerate and it sets many seeds. Once established in a lake, canal or marsh, it is almost impossible to eradicate. Salvinia is no different. These plants choke out all other life forms before drying up the lakes. They are a scourge to fisheries, agriculture and water transport.

Effects of - weeds

· Invade land and water area.
· Compete with native plants and crops for space, water, nutrients, light.
· Cause irritations and allergies.
· Poison animals and birds.
· Dry up water sources.
· Interfere with agriculture, aquaculture and waterborne transport.
· Require high expenditures for removal or eradication.
· Reduce native biodiversity of plants, fungi, insects.
· Suppress seedlings, causing poor regeneration of forests.


Any plant material must be certified by the exporting country as free of insect pests and diseases prior to export. Quarantine facilities must be established at the import points (airports and harbours) to monitor the performance of the plants. Genetic defects and effects are monitored in case of new plants species or varieties. The apex body in India for these services is the Central Plant Protection and Quarantine Centre in Faridabad, Haryana.

Suggested reference: George Usher, A dictionary of plants used by man. CBS Publishers and Distributors, Shahadara, Delhi.

Prepared by Miguel Braganza

5.7 Effects of pesticides on biodiversity

The continuing intensive chemicalization of the world's agriculture introduces large amounts of pesticides into the planet's biosphere-the habitat of all living beings, including humans.

As environmental contaminants, pesticides are different from other types of chemicals:

· It is nearly impossible to prevent their circulation in the biosphere.

· They are biologically active. This creates potential dangers to nature and people.

· A large proportion of the human population comes into contact with pesticides.

· Many pesticides persist in natural conditions and are transferred along the food chain.

· Many pesticides can be accumulated in the bodies of organisms that come into contact with even low concentrations.

Pesticides can have both lethal and sub-lethal effects on organisms they come into contact with.

· The average crop loss resulting from insects, diseases and weeds has been calculated as high as 35% of the potential production of crops.

· Pesticide consumption in India for agriculture and public health has risen from 2000 tonnes a year in the fifties to over 80,000 tonnes.

· Annually in the world, there are about 750,000 reported pesticides poisonings with about 13,800 deaths. India accounts for 1/3 of pesticide poisoning cases in the world.

· In nine weeks, earthworms can accumulate 18 ppm of DDT from soil containing only 1 ppm of DDT. This demonstrates the serious big-accumulation effects of pesticides in the environment.

· Per average of 76 mg/kg of pesticide residues have been found in samples of cow's milk obtained from local vendors in Bombay. This level is more than 500 times higher than the maximum intake level of 0.15 mg/kg recommended by WHO.

· The "Handigodu Syndrome" in the population of many rural areas in Kamataka was traced to the victim's diet of crabs found in ponds and rice fields which were contaminated with pesticides (endrin and parathion). Victims were crippled; their limbs, lips and shoulders became deformed.

· The major source of dietary intake of pesticide residues is human milk and milk products, followed by oils and fats.

Effects of pesticides on the environment


Potential effects


Presence of residual amounts in soil, water and air.


Presence of residual amounts. Damage due to phytotoxicity. Changes in vegetative development.


Presence of residual amounts in domestic and wild animals. Physiological actions (non-vitality of birds eggs). Extermination of some wild species. Development of second-generation pests.


Presence of residual amounts in tissues and organs. Occupational diseases.


Presence of residual amounts.

Organism being controlled

Development of resistance.

Biological transfer of pesticides

Pesticides enter a biological system by three main routes: aerial, terrestrial and aquatic.

Biological transfer of pesticides

Biomagnification of pesticides

The accumulation of pesticides in various biological systems is called "biomagnification". Some persistent pesticides accumulate in various biological system at levels much higher than those in their surroundings. For example, 1 kg of soil may contain only 1/1000 of a milligram of organochlorine pesticides-but a kilogram of carrots grown in the same soil may contain as much as 6 mg of pesticides.

Pesticides in the air

Pesticides enter the atmosphere mainly through the treatment of agricultural crops, seeds, forests, and water basins. They get into the air together with soil dust' via wind erosion, during soi! cultivation and crop harvesting. They are also evaporated from moist surfaces such as soil, water and plants. From the atmosphere, the pesticides and their metabolites get into water and soil and continue to circulate in the environment.

Aquatic environments

Pollutants, including pesticides, accumulate in sediments which serve as a habitat for various organisms in the aquatic food chain, which ultimately involves fish. Even in insignificant concentrations, some pesticides may change the taste and odour of water, have a negative effect on the process of oxygen formation by phytoplankton, and affect the vital activities of the inhabitants of the water ecosystems.

Pesticides are dispersed in water and are picked up by living creatures. The chemicals enter the food chain and accumulate faster in living organisms through the aquatic route than through the other routes.

Pesticides can have both lethal and non-lethal effects on fish. Non-lethal effects include disturbed population dynamics and changed food habits and reproductive behaviour. Pesticides such as DDT reduce the ability of fish to adapt to changing temperatures. They also result in vertebral fractures and can deform fish backbones and fertilized eggs. Fish can be used to indicate the level of pesticide contamination in water.


Sub-lethal dosages of pesticides can reduce the thickness of eggshells, making them fragile and reducing the number of eggs that hatch. Pesticides also cause hormonal changes in birds, influencing their courtship and nesting behaviours.

Pesticide degradation

When pesticide residues get into the hydrosphere, some are volatilized and lost to the atmosphere, some are degraded, some are incorporated in the biota, and some move into the sediment.

Animals, plants and micro-organisms are responsible for degradation and detoxification of pesticidal residues. Pesticides are modified or completely decomposed in the soil as a result of physicochemical processes, microbiological decomposition and absorption by higher plants and the soil fauna. The soils are rich in micro-organisms, which mostly include actinomycetes, fungi and bacteria. These micro-organisms play an important role in the degradation of pesticide residues from the soil. Many pesticides become detoxified by their adsorption by humus and other colloids or the formation of stable complexes in the soil. Poisonous chemicals are removed from the soil as a result of volatilization, evaporation with water vapour, migration beyond the root-habitat layer, washing out by rain water, melted snow, irrigation, ground and soil water.

Biomagnification in the food chain

When a pesticide enters the food chain, it can be deposited in the bodies of organisms. Predators that prey on large numbers of these organisms can accumulate large quantities of the pesticide. For this reason, the maximum accumulations of the toxicant are found at the top of the food chain.

The species affected depend on the predator-prey relationships in the food chain. For instance, a pesticide in the soil that is picked up by earthworms may end up in snakes:

Earthworm-bird- salamander-snake

A pesticide picked up by soil insects may enter a different food chain that also ends with snakes:

Soil insects-predacious insects-toad-snake

Some types of pesticides persist in the environment because they are not broken down easily into harmless substances. The use of persistent organochlorine pesticides like DDT and HCH for agricultural and nonagricultural purposes should be discouraged. They should be replaced with easily degradable "soft" pesticides of organophosphates, carbamates and synthetic pyrethroid group. Better still, integrated pest management approaches that avoid pesticide uses should be used to control pests.

Detoxification of pesticides in soil

Sources of pesticides

Pesticides can reach rivers, lakes, ponds and oceans from various sources:

· Industrial wastes and factory effluents
· Accidental spillage
· Spray drift at the time of field application
· Direct application to the soil for control of crop pests
· Atmospheric transport
· Agricultural wastes
· Sewage effluents.

Pesticide cycle in the environment

Alternatives to chemical pesticides

The dangerous side-effects of a number of conventional pesticides on wildlife, their human health hazards and their pollution of the environment have forced the discontinuation of their use or manufacture. In addition, many harmful insects have become resistant to synthetic insecticides. It has become imperative to find other ways of controlling pests.

Various approaches are used to control pests. Those using natural predators, parasites and pathogens (biological control), sexual sterilization, sex pheromones and insect growth regulators (third generation pesticides) appear to offer the greatest opportunity for success- particularly if used in integrated pest management programs.

Micro-organisms that affect insects, or "entomo-pathogens", induce diseases that often suppress and, in some cases, completely eliminate natural populations of insect pests. Over 1000 such pathogens have been isolated from insects. Many are associated with major pests and could be developed into microbial insecticides.

Plants are the richest source of renewable bioactive organic chemicals. Plant-based pesticides are the oldest pesticides used by man. Recently there has been renewed interest in botanical pesticides.

Prepared by Dr. Vijayendra P. Kamat

5.8 Khazan (saline) lands

The tidal estuaries of Goa stretch some 30 km inland. Either side of the estuaries lie "khazans": saline floodplains that lie below sea level at high tide. Over centuries, Goans have reclaimed these lands with an intricate system of dykes (bunds) and sluice gates. These barriers prevent salt water from entering the fields.

Eight of the 11 talukas (subdistricts) in Goa have a total of 17,500 ha under khazans. At least 2000 ha (12% of the total) are under dense mangrove vegetation. The mangroves help protect the outer side of the mud and laterite bunds that enclose the khazan. The total length of these bunds is about 2000 km.

Cultivation of the khazan lands dates back at least 3000 years. After 400 A.D., royal charters granted them to high-caste Hindu (Brahmin) settlers. Age-old co-operative, self-governing institutions known as gaunkaris or communidades reclaimed the khazan lands, engineered the intricate system of bunds and sluices, and maintained the khazan infrastructure. In 1975, this complex task was transferred to government-supervised "tenants associations". These are comprised of farmers who benefit from a particular protective bund. There are 138 such associations in Goa with a total of 20,000 farmer members.

Before reclamation

After reclamation


As a result of careful management of the khazans, the estuarine biodiversity has been largely retained and enriched despite population pressure in these areas. The khazans have a wide range of indigenous and introduced plant species, many tolerant to salinity.

Mussels, clams, oysters, crabs and prawns arc harvested seasonally and appear in village markets. The fish and shellfish sustain a large population of indigenous and migratory birds and the "mugger", or marsh crocodile.

Khazan and estuarine areas of Goa

Biodiversity of khazan and estuarine lands

Plants: Endemic and introduced
Mangroves: 15 species
Rice: 17 salt-tolerant varieties are cultivated
Grasses and weeds: 20 species
Fish and shellfish: 10 varieties of edible bivalves, 6 of mussels, and clams, oysters, crabs and prawns
Birds: Many resident and migratory birds
Crocodiles, other reptiles
Insects and other invertebrates not fully studied
Microflora: Salt-tolerant species of bacteria, fungi, algae and other microorganisms. 150 species of fungi so far known. Many potentially useful microorganisms have been found. Some can degrade oil, other petroleum products and pesticides. Others accumulate heavy metals such as iron and manganese.


Conditions in the khazan pose special problems for agriculture. The khazan soils are poorly drained and acidic (pH 4.8-5.3), relatively high in organic carbon and iron, and low in calcium.

Numerous types of wild rice have evolved to suit the saline conditions of the khazan. Over centuries, farmers have cultivated rice, selecting and replanting the best strains. In this way, new salt-tolerant varieties have developed, containing genes of enormous value to plant breeders. But these traditional varieties are gradually being replaced by modern, high-yielding varieties. The older varieties and their germplasm are disappearing.

Salt-tolerant rice varieties used in khazan farming


















Khazan land agro-ecosystem

Cost of a sluice-gate

There are about 600 sluice-gates in khazan areas of Goal Every year the wooden structure needs replacement. This structure is made from beams of local matti timber. Planks of mango or ghoting are used for shutters and horizontal beams. Each structure needs 100 cubic feet of wood and costs Rs 35,000.

Economic value of the khazan

Besides agriculture, the khazan ecosystem supports 200 ha of traditional salt manufacture, 2000 ha of coconuts and intensive fisheries.

It employs 40,000 farmers, 15,000 horticulturists and toddy-tappers (known locally as renderos), 10,000 fisherfolk and 10,000 others. These activities generate about Rs 150 to 250 million a year. It is estimated that more intensive sustainable use of the khazan land ecosystem could directly and indirectly generate a total of 115,000 jobs.

Impact of "development"

Development activities have had significant impacts on the ecology and economy of the khazan and estuarine areas.

Unfortunately the pace of degradation of the khazan ecology has increased in recent years. This is due to short-sighted planning, public apathy, industrialization and urbanization. The economic lives of the poor will continue to be affected, unless something is done to conserve or restore this complex and valuable ecosystem and its biological resources.

Employment types

1. Estuarine and tidal areas

· Fishing
· Shellfish collection
· Shell extraction for lime-making
· Boat transport

2. Embankments

· Building, supervision, repair, maintainance

3. Farming

· Cultivation of salt-tolerant rice during monsoon
· Pisciculture on co-operative scale after monsoon
· Intentional flooding every 3 years to kill weeds and pests

4. Plantation crops

· Mainly coconut. Also cashew, banana, mango, papayas, onions, chillies
· Seasonal crops
· Vegetables, tubers
· Salt production

The declining salt industry of Goa

From 1891 to 1991, the number of salt-producing villages in khazan areas of Goa dwindled from 36 to 13. The number of working salt pans fell from 268 to 119, and crude salt production declined from 40,000 t to just 18,000 t per year.


Ecological impact

Economic impact

Deforestation in river catchment

Increased sediment load, lower biodiversity

Shellfish industry declines

Uncontrolled urban growth

Overload on life-supporting systems

Housing, transport, sewage disposal problems

Pollution (effluents, solid waste, sewage)

Bioaccumulation of toxic residues, eutrophication, loss of aesthetic value

Rivers choked, aquatic life dies, lower fish catches, salt industry harmed

Barge traffic

Erosion of protective embankments

Rice and coconut crops decline; added maintenance cost


Increased heavy metal load

Agriculture, shellfish and salt industries harmed

Reclamation of low-lying land

Land-water equilibrium disturbed, other areas flooded

Flood damage, loss of pre-existing employment

Road and railway construction

Drainage pattern affected, erosion

Agriculture affected

Uncontrolled pisciculture

Increased soil salinity

Damage to rice, coconut and salt production; groundwater contaminated

Sand, shell and mud extraction

Erosion on bunds, destruction of subsoil fauna

Food chain damaged; soil conservation agents stressed

Slums and scrapyards on bunds

Vegetation cleared, land and water polluted

Local administration stressed

Unique agro-ecosystem

The khazan lands are a unique agro-ecosystem that has proven its sustainability through centuries of use. Although they are the result of conversion of natural estuarine ecosystems, they do not seriously alter either its physical or living components. Instead, the khazans work with existing natural features. Unlike many modern forms of agriculture, the range of agricultural species and varieties adds to the diversity of the estuaries.

Prepared by Nandkumar Kamat

Information kit produced by
WWF-India, Goa division and the
International Institute of Rural