Biology Revision Notes Of Economic Importance of Biology For NDA

PLANT BREEDING

Plant breeding is the purposeful manipulation of plant species in order to create desired plant types of early maturing, high yielding and disease resistant varieties. Plant breeding programmes are carried out in systematic way worldwide. In 1960, green revolution was came successfully by plant breedings. Dr. N E Borlaug is known as Father of Green Revolution in world.

Objectives of Plant Breeding

Plant breeding have following objectives
• To increase the yield and quality of crops.
• To develop disease resistant crops.
• To develop crops that are resistant to drought and salt.
• To develop high yielding varieties from less yielding varieties.
• To develop pest resistant crop.

`text(Principles of Plant Breediing)`
There are following principles of plant breeding

(i) Plant Introduction
• Plant introduction involves introducing plants from their natural habitat to a new habitat .
• This can be done by import or export of sexual or asexual reproductive structures.

(ii) Selection
• Individual plant or group of plants arc sorted out from mixed population, thus eliminating undesirable ones.
• The selection methods include mass selection, pure line selection and clonal selection.

(iii) Hybll'idisation
It is the method of producing new crop varieti·es, in which two or more
plants of unlike genotype (gcnetkally dissimila;:) are crossed.
Hybridisation can be
(i) intravarial,
(ii) intervarietal
(iii) interspecifie
(iv) intergerneric hybridisation
Hybrid It is an offspring of a cross between two genetically unlike individuals.

(iv) Polyploid Breeding
Polyploid breeding is done to produce plants with extra set of chromosomes.

(v) Induced Mutation
• Mutations arc the sudden permanent changes in the genome of organisms. These can be artificially induced with the use of X-ray,
rays, ')'-rays, UV-rays, etc. It can also be induced by chemicals such as mustard gas, etc.

• H J Muller (1927) first of induced mutation in Drosophila mclanogaster using X-rays. Base analogue of thymine is 5-bromo uracil.

(vi) Tissue Culture
Tissue culture technique is based on the totipotency (i.e. ability of a cell to give rise to whole plant) of plant cell.
The concept of totipotency was given by Haberlandt ( 1902) and detailed practical applications of totipotency was shown by Steward (1932), who
developed a complete carrot plant from a root cell. The part of plant used to generate whole plant is explant.
• Callus is a mass of cell developed due to redifferentiation in explant. Auxin and cytokinin arc important in tissue culture.
• Pisciculture is the practice of fish rearing involving proper utilisation of freshwater, brackish water and coastal areas.
• Edible fishes in India arc classified as major carps, e.g. Rohu, catla (both freshwater) and eel (marine) and minor carps, e.g. Calbasu (freshwater) and Hilsa (marine).
• In fish production, India is the second largest nation.
• Fishes are used for oil with vitamin-A and D.
• Clarification of wine and beer can be done by isinglass produced by gall bladder of fish.

Poultry

• The term 'poultry' means rearing of fowls, ducks, geese, turkey and some varieties of pigeons, but most often for fowls. Broilers are the poultry birds reared for meat and layers are the females birds raised for egg production.
• India ranks sixth nation in world for egg production.

Poultry Diseases

• Ranikhct disease (new castle disease) is the most common disease affecting the fowls of all ages. In this mortality rate is about 98-100%.
• Infectious coryza disease in poultry birds causes nasal and eye discharges with foul smell, acute respiratory problem and inflammed and swollen eyes.
• Bird flu is an avian influenza, caused by HSNl virus.

Apiculture

Apiculture (bee-keeping) includes the maintenance of hives of honey bees for the production of honey and bees wax. Honey bees are colonial, socialy polymorphic insects, which shows division of labour.

• In India, the commonly domesticated species are Apis mellifera (common European bee) and Apis indica (the small Indian bee).
• Honey is acidic in nature. It is composed of sugarcane (sucrose), which then converts into levulose (38.9'Yo), dextrose (21.28%), maltose and other sugars (8.81 %).
• Bees wax is a secretory product of hypodermal glands of worker bee's abdomen. It is yellowish to greyish brown coloured insoluble in water and soluble in organic solvents.
• Honey bees arc ecologically very important because they act as pollinator for many of our crop plants.

Sericulture

• Sericulture is the phenomenon of rearing of silkworm for commercial production of silk. India ranks second after China among the major silk producing countries of the world. There are five major types of silk produced in India, i.e. mulberry silk, tasar silk, muga silk, eri silk and oak silk.
• The catterpillars (larva) of the silkworm feed on their host tree and their salivary glands secrete liguid (pasty secretion), i.e. silk. Silk contains protein fibroin and sericin in 80:20 ratio.

• This silk when comes in contact with air takes the form of long thread of silk and is wrapped around catterpillar in form of covering called cocoon.
• Silk is obtained from six species of silk worm, i.e. mulberry silkworm (Bombyx mori), tasar silk worm (Anthemea paphia), muga silk worm (Antheraea assama), eri silk worm (Attacus ricinni), oak silk worm (Antherae pemyi) and giant silk worm (Attacus altas).
• Bombyx mori (mulberry silkworm) is a well known silkworm used commercially, which feeds on mulberry leaves. Diseases of silkworm are pebrine (protozoan), flacherie (viral or bacterial), muscaridine (fungal) and grasserie (viral).
• Castor, oak and teak leaves are commonly used for rearing silk worms.

Lac Culture

Lac is obtained from Indian lac insect Tachardia lacca or Kerria lacca. It lives on trees like banyan, sal, palash, beri, etc., and feed on the sap of host trees. The females are without wings, legs and eye. During unfavourable "season lac is secreted as a protective covering by females. In lac 68-90%, resin, 2-10% dye, 6% wax, 5-10% albuminous substance and 3-7% mineral are found. Lac is scrapped from twigs and processed to form shell lac. The shell lac is used in preparation of varnishes, paints, polishes, gramophone records, printing ink, buttons and pots, fillings of ornaments such as bangles and bracelets and as an insulating material.

Pearl Culture

Pearl is secreted by pearl oyster (Pinctada velgaris), a member of Mollusca phylum. Pearl is made of `CaCO_3` and cholkitin. Kokichi Mikimoto is the Father of Pearl Industry. Japan ranks first in the production of pearl.

MICROBES IN HUMAN WELFARE

The main uses of microbes for human welfare are given in the tables.

`text(5. Microbes in Medicines)`
Cyclosporin-A is derived from fungus Trichoderma polysporum, it is used as an immuno suppressant.
• Statins that lowers Bad cholesterol are produced from yeast.
• Also insulin, growth hormones, antibodies are produced by microbes.
• Microbes also play important role in genetic engmeenng.

ECONOMIC BOTANY

Economic botany includes the study of the utilisation of economically important crops such as cereal crops, vegetable, pulses, etc.

`text(Crop)`

On the basis of season, crops are of the following types
(i) Kharif Crop These crops are grown in the rainy season, i.e. from June to September, e.g. maize, bajra, red gram, paddy, soyabean, groundnut, cotton, millets, sarghum, moong bean, sugarcane as well tea, coffee, etc. These are called summer or monsoon crops.
(ii) Rahi Crop These are grown in the winter season, i.e. from October to March, e.g. wheat, barley, mustard, pea, scasame, green gram, linseed, etc.

Some Economically Important Crops

Oils and Fats

Oils obtained from plants, are of two types
(i) Essential oils Essential oils are aromatic and volatile. These contain terpenes, sulphuretted oil, oxygenated oils. These are useful in attracting insects and repel enemies.

(ii) Fatty oils Fatty oils present in plants are of three types
(a) Non-drying oil
(b) Drying oil
(c) Semi-drying oil
• Fats are solid/semisolid at room temperature. These are edible and are used in manufacturing soap and candles.

`text(Woods)`

• It is mainly secondary xylem formed by vascular cambium during secondary growth. The main function of the inner bark of a woody plant is to transport.
• Cricket bats are manufactured from the wood of Salix alba (Willow).
• Matchsticks and matchboxes are made of Salmalia malabarica, Boswellia serrate.
• Hocky sticks, tennis and badminton rackets, cricket stumps are made of Morus alba (hatoot), while pencils from the wood of Adina cordifolia, juniperus sp., etc.
• The wood produced by gymnosperm plants is commercially known as soft wood.

`text(Spices and Condiments)`

• They are generally hard parts of plants used in pulverised state for flavour.
• They can be obtained from different parts of plants, e.g.
(i) Turmeric, ginger from underground dried rhizomes.
(ii) Clove (laung), saffron (kesar) from dry stigma of flower.
(iii) Black pepper, coriande, fennel (saunf) from fruits.
(iv) Mint (pudina), peppermint from leaves.
(v) Cardamom (elaichi) and fenugreek (methi) from seeds.

MEDICINAL PLANTS

• Hippocrates is called the Father of Medicine.
• Depending upon the plant organ from, which the drug is obtained, the drug plants are divided into following categories.

`text(Drugs Obtained from Roots)`
• Belladona from Atropa belladona.
• Atropine alkaloid is obtained and used for dilating pupil of eye.
• Serpentine from Rauwolfia seroentina.
• About 30 alkaloids are obtained and out of which reserpine alkaloid is most important one having sedative influence.
• Ashwagandha from Withznia somnifera.
• It is used in treatment of rheumatic pain, inflammation of
joints, ulcers and to promote healing processes.

`text(Drugs Obtained from Leaves)`
• Tulsi from Ocimum sanctum.
• Its leaf juice is given in cold, cough and chronic fever.

`text(Drugs Obtained from Fruits and Flowers)`
• Opium from Papaver somniferum. It has great medicinal value.
• Saffron (kesar) from Crocus sativus. The dried stigmas and apps of the style are medicinally used. Lingeng is obtained from true ginseng. Acts as etinvlent and treat stomachache.



 
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