NEET Biology Strategies for Enhancement in Food Production Notes

Strategies for enhancement in food production cover animal husbandry, poultry, fisheries, bee keeping, sericulture, lac culture, plant breeding, single cell protein and tissue culture. This NEET Biology notes page on Strategies for Enhancement in Food Production explains cattle and buffalo breeds, dairy management, breeding methods, MOET, poultry and fish farming, honey bees, silk worms, selection, hybridisation, mutation breeding, genetic engineering, biofortification, SCP, tissue culture and somatic hybridisation, with check point questions and answers.

While going through the chapter pay special attention to the following -

Terms and Definitions -
1. Broiler 2. Pisciculture 3. Cocoon
4. Colostrum 5. Sericulture 6. Shagreen
7. Fisheries 8. Brooding 9. Poultry
10. Emasculation 11. Bagging 12. Electroporation
13. Single cell protein 14. Totipotency 15. Embryoids
16. Callus 17. Somaclonal variations 18. Homokaryons

Differences -
1. Round dance and Tail wagging dance
2. Bullocks and Oxes
3. Out breeding and Cross breeding
4. Roughage and Concentrates (food)
5. White revolution and Grey revolution

Diseases -
1. Anthrax 2. Ranikhet 3. Muscardine
4. Tick fever 5. Coccidiosis 6. Pebrine
7. Rinderpest

Breeds -
1. Plymouth 2. White leghorn 3. Murrah
4. Sahiwal 5. Surti 6. Pashmina
7. Kathiawari

Varieties -
1. Pusa Gaurav 2. Pusa sawani 3. Pusa A-4
4. Pusa sem-2 5. Pusa sem-3 6. Sonore-64
7. Lerma roja-64 8. Sharbati Sonora 9. Jaya
10. Ratna 11. Kalyan Sona

[Figure: At a Glance chart - Animal Husbandry: Live Stock (Cattle, Buffaloes), Dairy farm management, Artificial insemination, Infectious disease (Bacterial disease, Viral disease, Fungal disease, Parasitic disease, Protozoan disease), Poultry (Disease of poultry birds), Fish and fisheries, Insects and their products (Bee - Keeping, Silk Worm (sericulture), Lac Insects); Plant breeding: Selection, Hybridization, Mutation, Genetic engineering; Single cell protein; Tissue culture]

At a Glance

• Live Stock
  • Cattle
  • Buffaloes
• Animal Husbandry
  • Dairy farm management
  • Artificial insemination
  • Infections disease
    • Bacterial disease
    • Viral disease, Fungal disease
    • Parasitic disease
    • Protozoan disease
• Poultry
  • Disease of poultry birds
• Fish and fisheries
• Insects and their products
  • Bee - Keeping
  • Silk Worm (sericulture)
  • Lac Insects
• Plant breeding
  • Selection
  • Hybridization
  • Mutation
  • Genetic engineering
• Single cell protein
• Tissue culture

The earliest domesticated animal was dog - which is still used for watching, tracing criminals due to its keen sense of smell. (Huskies, the dogs, are used by Eskimos to draw sledges)

LIVE STOCK

Two important species of live stock are cattle and buffaloes. They are mainly used for milk. Bullocks are used for ploughing, harrowing, transportation, harvesting and threshing etc. Their hides are used for leather production; the horns, hoofs, bones etc. are used for preparing cattle feeds. Their dung is used for preparing cakes and bio-gas.

In the number of cattle and buffaloes, India ranks 5th. There are about 26 breeds of cattle and 7 breeds of buffaloes.

CATTLE (Bos primigenius indicus) - Indigenous breeds - 3- categories
1. Milch breeds - They are high milk yielding breeds. ex. Gir (Guj., Raj.), Sahiwal (Pb., UP), Red Sindhi (AP) and New Jersy.
2. Draught breeds- They are used for transportation. ex. Malvi (Raj., MP), Nageri (Hary., UP), Hallikar.
3. General utility breeds - ex. Kankrej (Guj.), Ongole (AP).

Exotic breeds- Holstein, Brown swiss, Jersy and Friesian.

BUFFALOES (Bubalus bubalis)
- They yield more milk of high fat content and have greater resistance and longevity ex. Murrah (Pb., Hary., UP), Surti (Guj., Raj), Bhadawari (UP, MP), Jaffrabadi (Guj.) and Mehsana (Guj).
- Food- 2- types , (i) Roughage- It includes high fibre content like hay, straw and fodder; and (ii) Concentrates- They include cereals, oil cakes, millets and oil seeds.

ANIMAL HUSBANDRY

- It is the agricultural practice of breeding and raising livestock. It deals with breeding and care of livestock like buffaloes, cows, pigs, sheep, goats, camels, horses etc. which are useful to human. The fisheries, poultry farming, apiculture and sericulture are also listed in animal husbandry.
- More than 70% of livestock population of the world is in India and China. But their contribution in farm products is about 25% only. This indicates that per unit productivity is very low. This is because of traditional or conventional farm management practices. Now, newer technologies need to be applied for improvement in quality and productivity.

Dairy farm management

Dairying is the management of animals for milk and its products for human consumption.

The dairy farm management deals with the processes and systems that increase the yield and improve the quality of milk. Such processes depend upon
1. Quality of breeds
2. Climatic conditions of the area
3. Proper maintenance and housing
4. Quality and quantity of feed/ fodder
5. Cleanliness and hygiene of both cattle and the handlers
6. Proper storage and transportation of the milk and its products
7. Regular visits by a veterinary doctor

Animal breeding

The basic aim of the animal breeding is to increase the animal yield and improve the desirable qualities of the produce.

[Figure: Fig. 9.1 Jersey breed (Cattle)]

Breed

It is a group of animals of common descent with common features. The breeding can be of 2-major types
1. Inbreeding
2. Out breeding

Inbreeding

- It is the breeding between the animals of the same breed.
- The superior breeds of male and female cattle are selected for mating to develop pure lines. Inbreeding increases homozygosity and exposes harmful recessive genes by selection.
- However, the continued breeding of closely related animals usually reduces fertility and productivity. This is called Inbreeding Depression.

Out breeding

It is the breeding between unrelated animals, and can be of 3- types :
1. Out crossing : It is the cross between the members of the same breed which have no common ancestors for 4 to 6 generations. A single out cross often helps to overcome Inbreeding depression.
2. Cross breeding : It is the cross between the members of different breeds but of same species. This allows the desirable qualities of two different breeds to be combined. Hisardale is such a breed of sheep, developed in Punjab, by cross breeding Marino ram and Bikaneri ewe.
3. Interspecific hybridization : It is the crossing between the members of different species, e.g., Mule and Hinny. The Mule is a hybrid between male Donkey and female Horse; whereas Hinny is a hybrid between male horse and female donkey.

Artificial insemination

When semen, collected from a high pedigreed male is transferred into the reproductive tract of selected female by the breeder, it is called artificial insemination. The collected semen may be used immediately or can be frozen for the use at later stage, or can be transported to far off places. The success rate, even after artificial insemination for breeding, is very low . To improve the chances of successful mating for the production of better breeds, a new technology, called Multiple Ovulation and Embryo Transfer technology (MOET) is being used for cattle and other animals. In this method the females are administered extra doses of FSH like hormones to induce maturation of several follicles and thus super ovulation, for getting 6 to 8 gametes
(eggs) per cycle. Such females are either inseminated artificially or mated for fertilized eggs. The embryo at 8 to 32 celled stage are then transferred to surrogate mothers. The genetic mother, a high pedigreed one, now becomes available again for another round of super ovulation. This technique has been employed to produce high quality meat (Lean meat- with low fat content) or better milch breeds.

Milk and its composition : ‘Milk’produced by animals immediately after parturition (for 3-10 milkings) is called Colostrum. It is rich in proteins, vitamins and antibodies. The protein content (mainly Casein) in the milk of cows is 3.3g %, in buffaloes-4.3g %. In human it is very low (1.0g %).As compared to cows’milk the fat content in buffaloes’ milk is more than double. The carbohydrate content (mainly lactose) in cows and buffaloes milk is 4-5g % while in human it is the maximum (7.5g %).
- Father of white revolution (related to milk and dairy products) in India is Verghese Kuriene.
- National Dairy Research Institute, established during first 5- year plan, is at Karnal (Hary).
- Indian Veterinary Research Institute is at Izatnagar (UP).

Diseases of live-stock

They may be caused by pathogens (Infectious diseases), improper nutrition (Deficiency diseases) or due to genetical factors (Hereditary diseases).

[Figure: Fig. 9.2 Mule]

INFECTIOUS DISEASES

1. Bacterial diseases Tuberculosis, Anthrax and Mastitis
(a) Tuberculosis- In this disease dry cough and fever develops due to lung infection. The milk is affected and the disease may be transmitted to man through milk.
(b) Anthrax- It is caused by Bacillus anthracis and spreads to other animals through contaminated food and water. It is contagious and can pass to human beings also.
2. Viral diseases e.g. Rinderpest, blue tongue, Foot and mouth disease (caused by the smallest virus (~200 Å), of picorna group) and cow pox Rinderpest, also called cattle plague, is contagious disease in which the virus is present in the fluid and secretion of the diseased animals. It can be transmitted through contaminated food and water, and flies.
3. Fungal diseases e.g. Ring worm The infected animals show rounded scabs over the affected part.
4. Parasitic diseases e.g. Ascariasis (Round worms), liver rot (Liver fluke), Taeniasis (Tape worm) etc.
5. Protozoan diseases e.g. Tick fever (Texas fever)

Prevention of infectious diseases -
- Isolation of suffering animals
- Disposal of carcasses
- Proper disinfection and cleaning of animal houses
- Vaccination or injection of antiserum

POULTRY

Poultry farming- It is rearing of Fowls, Ducks, Turkeys and Pheasants for their eggs and meat.

The poultry products are rich source of protein, Minerals and fat etc.

Poultry farming is advantageous over live-stock rearing in following aspects -
- Easy to raise
- Easy acclimatization to wide range of climatic conditions
- Short life span
- Prolific or fast breeder (60 to 240 eggs/year)
- Require less space for management
- Fast returns of income (within 6- months) (The revolution related to eggs - production is called Silver revolution).

Domestic fowl (Gallus domesticus) has evolved from Red Jungle fowl (Gallus gallus), and are of 2 types -

I. Indigenous (Desi type) - Aseel (AP), Ghagus (AP) and Chittagong (WB)
- Aseel is a good table bird (for meat) but not good sitter or layer (for eggs). It has black or white plumage and is used in cock- fighting.
- Chittagong has golden yellow plumage. It is a good layer as well as a good table bird.

Ghagus has variable plumage and is useful for both meat and egg.

II. Exotic (Improved type)- 4- classes i. American class - Plymouth, Rhode Island and New Hampshire ii. Asiatic class - Langshan, Brahma and Cochin iii. English class - Sussex and Australop iv. Mediterranean class - White Leghorn and Ancona

[Figure: Fig. 9.3 Leghorn breed (Poultry)]

(Poultry)

Most popular poultry bird in India is white Leghorn.
- Broilers - The birds exclusively grown for meat (ex. Plymouth rock).
- Heterosis - Better egg- layers. (India is world’s 5th largest egg producer and 18th biggest producer of broilers).
- Incubation - Maintenance of newly laid eggs in optimum conditions till hatching.
- Brooding - Care and management of chicks for 4 to 6 weeks after hatching.

For poultry farming there should be
1. Selection of suitable breed
2. Proper food and water
3. Hygiene and health care
4. Proper and safe farm conditions Diseases of poultry birds
- Viral diseases- Bird Flu (H5N1), Ranikhet (New Castle disease) and Fowl pox. These are contagious, highly infectious and fatal.
- Bacterial diseases- Tuberculosis, Fowl cholera, Tick fever and Pullorum, Coryza.
- Protozoan diseases- Coccidiosis, caused by Eimeria.

FISHES AND FISHERIES

- Ichthyology : It is the scientific study of fishes.
- Pisciculture : It is rearing of fishes at commercial level.
- Fisheries : It is rearing, capturing (harvesting), marketing and management of commercially important fauna of fresh water and sea water bodies.
- Inland Fisheries : It is rearing of fishes or other commercially important fauna in fresh water. The other types are marine fisheries and estuarine fisheries.
- Aquaculture : It is production of useful fauna and flora such as algae, fishes, prawns, shrimps, crabs and pearl- oysters etc. at commercial level by proper utilization of small and large water bodies.

Fishes are economically important because
- They provide meat- a rich source of protein, which is very nutritious and easily digestible.
- They provide oil for soap and paints.
- Cod liver oil and shark liver oil are rich sources of vitamins A and D.
- Shark skin , called Shagreen, is used for making hand bags and purses. It is also used as abrasive.
- They are also used in aquarium.
- Their non- edible parts like fins, bones and tails etc. are used for preparing cattle and poultry feed.
- The Isinglass, obtained from Air bladder of teleosts, is used for clearing wine. (The revolution in commercial production of fishes is called Blue revolution).

Fresh water fishes

Labeo rohita (Rohu), Catla catla (Catla), Mystus cinghala (Singhara), Clarias batracus (Magur), Wallago attu (Malli), Heteropneustes (Singhi) and common carps (fam.

Cyprinidae).

Marine fishes

- Harpodon (Bombay duck), Hilsa, Salmon, Mackerel, Sardine, Stromateus (Pomphret).
- Anabas, the climbing perch, has gill- chambers it its mouth to gulp-in and store air. The fish can move short distances on land by ventral fin.
- Latimeria or Coelacanth fish is a lobe- finned fish without lungs and without fin- rays.
- Cyprinis- a European carp, is an exotic fish which has been introduced in India from China.

INSECTS AND THEIR PRODUCTS

Bee keeping (Apiculture) :

- Honey bees (OrderHymenoptera) are used for the production of honey and wax. Their bite or sting is sometimes helpful for treating muscular pain or rheumatism. Amongst insects the bees are the best pollinators.
- Apiculture or Bee Keeping : It is rearing of honey bees for the production of honey and wax at commercial level.
- Apiary : It is the place where honey bees are reared.

The important species of honey bees are-
1. Apis dorsata (Rock bee)- It is the largest honey bee and produce 15- 30 kg honey / comb. It is ferocious and difficult to domesticate.
2. A. indica - It is the most commonly domesticated honey bee in India and other parts of world. It produces 5-15 kg of honey/comb.
3. A. florae - Little bee. It has little commercial value

[Figure: Fig. 9.4 Honey bee (Apis) and Honey comb (Hive)]

(Apis mellifera - Italian honey bee, is commercially exploited in other parts of the world).

Adults- morphology It is a polymorphic and social insect having well developed caste system. It has 3- castes or forms
1. Workers - They are the smallest members of the colony but are maximum in number. They are diploid and sterile individuals. Their fore and mid legs have pollen brushes and hind legs have pollen basket and pollen comb for the collection of pollen grains. They have barbed sting. They produce honey in crop and the wax from cutaneous wax glands. Their life span is 2-4 months (maximum upto 1 year).
2. Queen - She is the biggest/largest member of the colony. It lives upto 5 years, but mates only once in a life time. There is one queen in the comb. It is a fertile and diploid individual. The Pollen basket and wax glands are absent but sting without barbs is present.
3. Drones - They last for one breeding season and are driven out of the hive (comb) in the following summer. They are fertile, haploid and male individuals of the colony. The Pollen structures, wax glands and sting apparatus are absent.

(The Workers and Queen develop from fertilized eggs whereas Drones develop from unfertilized eggs).

Developmental stages - Egg → Larva or Grub → Pupa → Adult (Holometabola insect)

The period (duration) of development, from egg to adult, in the 3-castes is as follows :
(i) Workers - 21-days; (ii) Queen - 16-days; (iii) Drones - 24-days;
- Bee dances : Workers perform dances for communicating the source of food. Prof.

Karl.
- Von Frisch (1969) got Nobel prize for decoding their communication language. Dances - 2- types.
1. Round dance- It is performed by workers when the source of food material is within 50-75 mts. In such a dance the direction of food is not indicated.
2. Tail wagging dance- It is performed when the food is more than 75 mts. away. It conveys the direction of the food from the sun.

Honey

- It is a produce (not secretion), formed in the crop from the pollens and nectar by enzymatic action.
- It contains Fructose, Glucose (Dextrose and Levulose), Sucrose and Dextrin sugars, and is the oldest sweetening agent.
- It is a laxative (prevents constipation).
- It is a blood purifier and builds up haemoglobin.
- It mainly contains Vitamin B1, B6 and C.
- It is also used in confectionary and alcohol industry.

Wax

- It is the produce or secretion of abdominal wax glands of 4th to 7th sterna. It is used in preparations of shaving cream, tooth paste, face cream and lotions, polishes, ink and paints etc.
- (The Propolis, called Bee-glue, is prepared from resin, collected by the bees from plants, and is used by honey bees for filling cracks and crevices of the cells of honey comb).
- The bee-keeping is an age old cottage industry. It is practiced in areas of wild shrubs, fruit orchards and cultivated crops. The bee-keeping is not a labour intensive industry. The most common species of honey bee is Apis indica.

For bee-keeping one should have the knowledge of
1. Nature and habits of bees
2. Suitable location for keeping bee-hives or apiary
3. Catching and hiving of swarms
4. Management of bee hives during different seasons
5. Handling of bees and collection of honey and bee wax.
- Keeping bee hives in crop fields during flowering period increases pollination and hency crop yield and also honey yield. The bees are pollinators of Brassica, Apple and Pear etc.

SILK WORMS OR SILK MOTHS (SERICULTURE):

- Sericulture : It is the breeding and management of silk worms (order Lepidoptera) for the production of silk at commercial level. Silk production started in China and there from the cocoons were smuggled to India by monks.

Type of silk worms- i. Mulberry silk worms, ii. Non- mulberry silk worms I. Mulberry silk worm (Bombyx mori) - It is wholly domesticated and is reared on the leaves of mulberry tree (Morus alba).

II. Non-mulberry silk worms - Their worms or larvae (caterpillar) do not feed on mulberry- leaves. They are of 3- types
1. Eri silk worm (Philosamia or Attacus ricini)- Its larvae feed on the leaves of castor (Ricinus communis) and produce eri silk, called poor man’s silk.
2. Tasar silk worm (Antherea mylitta or paphia)- Its larvae feed on the leaves of Arjuna or Saal (Shorea robusta) and produce Tasar silk.
3. Muga silk worm (Antherea assama) - The worms feed on the leaves of Som plant. Muga or munga silk is costlier one.
- India is the only country which produces all the four varieties of natural silk at commercial level.
- However, a 4th variety of silk, Oak silk by Antheria proylei - a hybrid of A. pernyi and A. roylei, is also being exploited commercially, but at low pace.
- India ranks 3rd among the mulberry silk producing countries and 2nd among the tasar silk producing countries of the world. Muga silk is produced only in India (Assam).
- Adults- morphology : In Bombyx mori, the adults are small creamish winged moths with vestigial mouth parts and short life span.

[Figure: Fig. 9.5 Bombyx mori (Silk moth) and Larva (Caterpillar)]

- Developmental stages - Egg → Caterpillar (Worm or Larva) → Pupa → Adult (Holometabola Insect).
- The silk is secreted by larvae or worms from their silk glands which are modified salivary glands. This silk is used for making cocoon to enclose pupa. The silk is commercially obtained from cocoons.
- The silk is chemically a protein (a β- pleated structure). Its inner core is formed of Fibroin protein that makes 70 - 80 % of filament while outer coating contains albuminous protein called Sericin.
- Silk if burnt gives a smell of burnt feather.

Diseases of silk worms

- Protozoan diseases- Pebrine, caused by Nosema sp. Its spores can pass through eggs. It is highly fatal.
- Bacterial diseases- Flacherie, Sotto.
- Viral diseases- Grasserie, Flacherie (also caused by bacteria), Polyhedrosis.
- Fungal diseases- Muscardine- It is a contagious and threatening disease for larvae.

Lac Insects

- Lac industry - It is the rearing of lac insects for production of lac or shellac at commercial level.
- Lac insect (Laccifer or Tachardia lacca) - a bug of order Homoptera - feeds on host plant - Ber (Ziziphus jujube) and Kusum (Schleihera sp).
- Lac cultivation begins with Brood lac, an encrustation containing insects, on the twig of a host tree. The insect breeds over there and secretes lac. The raw product is scrapped from the branches and processed through a hot melting process to produce Shellac ( the commercial name of lac).
- Kauravas built a palace of lac (Lakshagrah) to kill Pandavas.

Morphology of insect
- Males- They are larger and have well developed wings and legs.
- Females- They are degenerate forms and do not have wings, legs and eyes.
- Nymphs- They are young ones and wingless.
- It is Hemimetabola insect.

It is female insect that produces or secretes bulk of lac. Lac globules are also secreted by the nymphal stages. Lac is produced from the epidermal or cutaneous glands all over the body. There are 2- crops per year- Rajni and Kusumi (named after Hindi names of plants)

Lac : It is a resin and is the only resin of animal origin. It is commonly called sealing wax. It is used in varnishes, polishes, printing ink, gramophone records and as a stiffner in leather and jewellary finish.

PLANT BREEDING

- Plant breeding refers to the modification and improvement of genetic material of plants resulting in the development of crops which are more beneficial to human beings.
- This improvement may be in following respects :
(i) Quantitative characters : Increase in yield of seeds, fruits, grains, fibres, oils, etc
(ii) Qualitative characters : Increase in biochemical components like proteins, fats etc.
(iii) Resistance againts diseases, insects, pests, drought, frost, salinity, exterme temperatures etc.
- Pusa Gaurav variety of Brassica is resistant to aphids.
- Pusa Sawani & pusa A-4 varieties of Okra (Bhindi) are resistant to shoot & fruit borer.
- Pusa sem 2 & pusa sem 3 variety of flat bean are resistance to aphids & fruit borer.
(iv) Change in maturity period and behaviour.
- It is difficult to establish time of origin of plant breeding.
- It is assumed that modern age of plant breeding started in the early twentieth century, after Mendel’s work was rediscovered.
- Today the science of plant breeding aims towards development of superior quality of crop plants involving various methods including mutation, tissue culture, genetic engineering, etc. The various methods of crop improvement are -
1. Selection 2. Hybridisation 3. Mutation 4. Genetic engineering.

Selection

- Selection is the oldest method of crop improvement. Almost all our present day crops are developed from the selections carried out by the prehistoric human beings. In selection, plant having the desired characters are picked up from a population eliminating the undersirable ones.
- These selected plants are allowed to reproduce for setting their seeds. The seeds are collected and again a new crop is developed.
- Selection is again done in this new crop. Thus, the process of selection, which started in the prehistoric times, is still continuing.
- As a result, our present day crop plants are entirely different from their wild ancestors and probably their wild ancestors have disappeared from the nature. For example, maize and cabbage are represented only by their cultivated varieties.

Connecting Concepts
- N.E Borlaug is the famous Mexican plant breeder, known as father of green revolution. He developed high yielding wheat varieties like sonora-64, Lerma roja-64 etc.
- Dr. M.S. Swaminathan : He is called father of green revolution in India. He had produced Sharbati Sonora variety of wheat which is responsible for green revolution in India.

- There are two important methods of selection - (a) Mass selection and (b) Pure-line selection.

Mass selection

- It is the oldest and most common method of crop improvement.
- In this method, a large number of plants of a species with similar phenotypic characters (or external appearance) are selected and their seeds are sown in the fields for progeny testing.
- Plant with superior traits among the progeny are selected. The selection is repeated till the desired improvement in the crop is achieved.
- This method is of great advantage in case of self pollinated crops where the plants are usually homozygous and retain selected traits in the progeny.
- It is not useful in cross pollinated crops which are usually heterozygous and may lose the desired phenotypic character in the subsequent generations.

Pure-line selection

- The self pollinated progenies of homozygous plant forms a pure line.
- In this method, a plant with desired characters is selected from a genetically mixed population. The single selected plant self-pollinated for generations to select a true breeding species with desired characters.
- Once the homozygosity is confirmed, the individual is multiplied on a large scale and recommended to the farmers.

Hybridisation

- Crossing between the two genetically diverse parents to obtain a progeny with the desired traits is called hybridisation.
- When a hybridisation is performed between the two plants, it is called single cross and when it is performed between more than two plants, it is called multiple cross.
- A hybridisation may be
(i) Intravarietal (between the two plants belonging to same variety).
(ii) Intervarietal or Intraspecific (between the two varieties of the same species).
(iii) Interspecific (between the different species of the same genus).
(iv) Intergeneric (between two different genera).

Method of Hybridisation

- Hybridisation in plants involves the following steps :
(i) Selection of parents with desired characters : The first step of hybridisation is to select two parents (one male and the other female) which possess the desired characters.
(ii) Emasculation : Removal of stamens or anthers or killing the pollen grains of the flower is called emasulation.
- It is necessary in bisexual flowers to prevent self-pollination.
- By emasculation a female flower can be artificially pollinated by the desired pollen grains.
(iii) Bagging : The emasculated flower is immediately enclosed in bag (made of paper, cloth or plastic) to avoid pollination by any unwanted pollen. The process is called bagging.

Connecting Concepts
- Proteins of cereals and millets are deficient in two amino acids lysine and tryptophan whereas those of pulses are deficient in methionine and cysteine. Therefore, plant breeders are trying to develop varieties of cereals and millets which are rich in lysine.
- Oil and fats are made up of (i) Saturated and (ii) Unsaturated fatty acids. Polyunsaturated fatty acids are beneficial to human health in contrast to long chain saturated fatty acids. Plant breeders are trying to develop such varieties of oil seeds which are rich in polyunsaturated fatty acids.

(iv) Pollination : During artificial pollination, the mature and viable (fresh or stored) pollen grains are collected from the male parent, the bag is opened and the pollen grains are dusted on the stigma.

Mutation

- Mutation is a sudden, stable and heritable change which alters the genotype of an organism.
- Mutations cause variations which are not always useful but in a few cases they are useful in breeding programes.
- The mutations, which are artificially induced by treatment with certain physical or chemical agents, are called induced mutations.
- The application of induced mutations for crop improvement is called mutation breeding.
- The agent which are used to induce mutations are called mutagens.
- Some common mutagens used in mutation breeding are -
(i) Short-wave electromagnetic radiations (e.g., ultra-violet, X-rays, cosmic rays, etc.).
(ii) Ionising radiations (e.g., gamma rays obtained from radioactive isotopes 60Cobalt and 137Cesium).
(iii) Chemicals (e.g., nitrous acid, ethylmethane-sulfonate or EMS, nitromethyl urea, mustard gas, colchicine), etc.

Genetic Engineering

- It is latest method in breeding programme which involves transfer of one or more genes (i.e., DNA fragment) from one plant to another.
- The plant in which a foreign gene(s) has/have been introduced is called transgenic plant.
- There are two distinct techniques for introducing foreign genetic material into plant cell genome.
- The first, through a vector, requires selection and isolation of the desirable fragment of DNA ligated to a vector (i.e., the bacteria - Agrobacterium tumefaciens, a virus or any other vector) and introducing novel genes into plant cells.
- The second, through direct introduction of DNAthrough electroporation (i.e., application of electric impulses to change the porosity of protoplasts so that they directly imbibe the purified DNA) and micro-injection (i.e., direct injection of DNA with the help of a micro-pipette).
- Successful genetic engineering requires a thorough knowledge and identification of the desired genes, their transplantation, integration and expression.
- Exact organization and location of specific genes in crop plants as there are about one to ten million genes in each crop plant. Therefore, a thorough study is yet to be discovered about the genome organization of crop plants and their wild relatives before manipulating their genetic material for crop improvement.

Examples of some improved varieties :
(1) Wheat : Sonalika, Kalyan Sona, Himgiri.
(2) Rich : Jaya and Ratna.
(3) Sugar cane : A variety obtained by crossing Saccharum barberi and Saccharum officinarum.
(4) Brassica : Pusa swarnim (resistance against white rust).
- Biofortification is the improvement of nutritional quality of crops to improve public health.
- In plant breeding, biofortification aims at developing new crops with improved
- protein content and quality
- lipid content and quality
- vitamin & mineral content
- Some biofortified vegetables developed by plant breeding programme are -
- Vitamin A enriched carrot, spinach, pumpkin
- Vitamin C enriched mustard, tomato
- Iron and calcium enriched spinach and bathua
- Protein enriched beans-lablab, French beans

SINGLE CELL PROTEIN (SCP)

- Single cell protein refers to the dried microbial cells or total protein extracted from pure microbial cell culture (algae, bacteria, yeasts & filamentous fungi) which can be used as food supplement to humans or animals.
- The term single cell protein (SCP) refers to the fact the most of that microorganisms, used in the production of SCP, are unicellular.

Some common microbes as SCP producers Basically, single cell proteins are the dried cells of microorganisms belonging to bacteria, yeasts, moulds, fungi and some algae.
(i) Bacteria : Methylophilus methylotrophus, Brevibacterium sp., etc.
(ii) Cyanobacteria : Spirulina
(iii) Yeasts : Saccharomyces cerevisiae, Candida utilis etc.
(iv) Filamentous fungi : Fusarium graminearum, Chaetomium cellulolyticum, etc.
(v) Algae : Chlorella, Scenedesums, etc.

Advantages of SCP
- It has high protein and low fat content.
- It is good source of vitamins particularly B-complex. e.g. Mushrooms and Yeasts.
- It can be produced through-out the year.
- Waste materials are used as substrate for the production of these proteins. It reduces the environmental pollution and helps in recycling of materials.
- SCP organisms grow faster and produce large quantities of SCP from relatively small area of land and time.
- These have proteins with required amino acids that can be easily selected by genetic engineering.
- During the production of SCP biomass, some organisms produce useful by products such as organic acids and fats.

TISSUE CULTURE

- Plant tissue culture is defined as the maintenance and growth of plant cells, tissues and organs on a suitable culture medium in vitro.
- Totipotency is the ability of a plant cell or part to grow into a whole plant.
- When cultured in suitable culture medium at appropriate temperature and aeration conditions. This ability of cell is used in tissue culture, a method of plant proportion and improvement.
- The part of the plant which is used in tissue culture is called explant.
- Explant may be excised root tips, shoot bud, leaf petiole, inflorescence, anther, ovule, ovary or embryo.
- Embryoids are embryo-like structures derived from vegetative cells.
- Plants produced by tissue culture method are genetically identical to the original plant and known as somaclones.
- Culture medium should provide nutrition that is required for the desired growth & development of the explants. It contains a carbon source (sucrose) and is enriched with inorganic salts, vitamins, growth regulators (auxins & cytokinins).
- Callus is the cluster of cells produced by tissue culture.
- The callus generally consists of parenchymatous cell. The fresh tissue formed in the form of callus may be separated from explant and transferred to fresh medium to avoid conjested growth, shortage in supply of nutrients and medium drying.
- Shoot formation in callus is initiated by cytokinins.
- Auxins promote root formation in callus.
- Aseptic conditions (germ free conditions) are maintained by preventing entry & growth of microbes, which can compete with growing tissue & finally kill it.
- Somaclonal variations are genetic variations present in the cells of a callus.
- Anther culture produces haploid plants, discovered by Guha & Maheshwari (1961) in Datura.
- Anthers are cultured directly on liquid or semi-solid media. The microspores of anther directly develop into embryos or may form a callus which is indirectly regenerated to produce haploid plants. Sometimes, pollen grains are separated from anthers and cultured on suitable media.

Embryo Culture

- Mature embryos can easily be excised and cultured on artificial medium containing only few mineral salts and sucrose. Since they are mostly autotrophic in nature, they require a little amount of nutrient from outside.

Ovule Culture

- Culturing of fertilized ovules is sometimes needed in those cases where embryos abort very early and the culture of embryo is not possible due to difficulty in excission at a very early stage.
- Ovules can easily be excised from the ovary and cultured on the usual nutrient medium.

Protoplast fusion and Somatic hybridization

- Culture of fused protoplasts produces somatic hybrid cells and the process of producing somatic hybrids are called somatic hybridization.
- Various new species have been developed through this technique.
- Protoplasts are cells with their cell walls removed.
- Removal of cell wall is done by enzymes like cellulase and pectinase.
- The somatic hybridization helps in transfer of desirable characters from wild or unrelated crops species to our crop plants.

[Figure: Somatic hybridization - Plant cell treated with Cellulase + Pectinase gives Protoplast (plant cell lacking cell wall); Parent A protoplast and Parent B protoplast are fused with Polyethylene glycol (PEG) (Cell fusion), followed by Nuclear fusion to form a Somatic hybrid cell]

- The fusion of protoplasts is done by two methods (i) Spontaneous fusion and (ii) Induced fusion.
- Spontaneous fusion occurs during the isolation protoplasts. It results in the formation of homokaryons.
- However, spontaneous fusion can also be induced by bringing protoplasts into intimate contact through microtechniques.
- Induced fusions of protoplasts are brought by the treatment of Sodium nitrate, Calcium ions at high pH, polyethylene glycol or by electrofusion.
- Successful somatic hybridisations have been done in many crop plants. The first somatic hybrids were obtained by somatic hybridisation between Nicotiana glauea and N. longsdorfit.
- Somatic hybrids have also been found between the species of Brassica, Petunia and Solanum.
- Pomato is an example of intergeneric somatic hybridisation between potato and tomato.
- In embryo culture embryos taken out from seeds and grown on culture medium. The embryos might be obtained from
- seeds of interspecific hybrid plants (embryo rescue).
- seeds which lack stored food e.g., orchids.
- seeds which are dormant.
- seeds of rare plants.

CHECK POINT QUESTIONS

1. Fill in the blanks, each with a suitable word or statement :

(i) The earliest domesticated animal was ............... .

Answer: dog

Teacher's Note:
a) Dogs are still used for watching and tracing criminals because of their keen sense of smell.

(ii) Sahiwal and Red Sindhi are ............... breeds of cattle.

Answer: milch (high milk yielding)

Teacher's Note:
a) Draught breeds such as Malvi and Nageri are used for transport and ploughing.

(iii) The reduction in fertility and production due to inbreeding is called ............... .

Answer: inbreeding depression

Teacher's Note:
a) A single out cross often helps to overcome it.

(iv) The mating between animals of the ………… breed/s is called out breeding.

Answer: unrelated (no common ancestors for 4 to 6 generations); this may be the same breed (out crossing) or different breeds (cross breeding)

Teacher's Note:
a) Out breeding is of three types: out crossing, cross breeding and interspecific hybridization.

(v) The cross of ............... and ............... produces mule.

Answer: male donkey and female horse

Teacher's Note:
a) A hinny is the reverse cross: male horse and female donkey.

(vi) ……………………. is the expanded form of MOET.

Answer: Multiple Ovulation and Embryo Transfer technology

Teacher's Note:
a) FSH like hormones induce super ovulation and the embryos at 8 to 32 cell stage go to surrogate mothers.

(vii) National dairy research institute is located in ……………

Answer: Karnal (Haryana)

Teacher's Note:
a) The Indian Veterinary Research Institute is at Izatnagar (UP).

2. Mark 'True' or 'False' against following statements:

(i) Rinderpest is a disease of cattle.

Answer: True

Teacher's Note:
a) It is also called cattle plague and is a viral disease.

(ii) Indian veterinary research Institute is at Izatnagar (UP)

Answer: True

Teacher's Note:
a) Remember the pair with NDRI at Karnal.

(iii) Texas fever is a bacterial disease of cattle.

Answer: False. Texas (tick) fever is a protozoan disease.

Teacher's Note:
a) Rinderpest and foot and mouth disease are viral, anthrax is bacterial.

(iv) Revolution related to milk and dairy products is called white revolution.

Answer: True

Teacher's Note:
a) Verghese Kurien is called the father of the white revolution in India.

(v) More than 70 % of live stock population occur in India and China.

Answer: True

Teacher's Note:
a) Their contribution to farm products is only about 25 percent, showing low productivity per unit.

3. Fill in the blanks, each with a suitable word / statement :

(i) The revolution related to eggs is called ................

Answer: Silver revolution

Teacher's Note:
a) Blue revolution is for fishes and white revolution for milk.

(ii) ............... is a marine fish and is commonly called Bombay Duck.

Answer: Harpodon

Teacher's Note:
a) Hilsa, Salmon, Mackerel and Sardine are other marine fishes.

(iii) The birds exclusively grown for meat are called ...............

Answer: Broilers

Teacher's Note:
a) Plymouth rock is an example.

(iv) ............... is the rearing of fishes at commercial level.

Answer: Pisciculture

Teacher's Note:
a) Fisheries cover rearing, capturing, marketing and management.

(v) ............... is a Mediterranean breed and is the most popular bird in India.

Answer: White Leghorn

Teacher's Note:
a) Ancona is the other Mediterranean breed.

(vi) The orthomyxovirus (H5N1) causes …………………..

Answer: Bird flu (avian influenza)

Teacher's Note:
a) It is a viral disease of poultry along with Ranikhet and fowl pox.

(vii) …………….. is European carp that has been introduced in India from China.

Answer: Cyprinus (common carp)

Teacher's Note:
a) It is an exotic fish.

(viii) Ranikhet is the disease of ………………

Answer: poultry birds (fowl); it is also called New Castle disease

Teacher's Note:
a) It is a contagious and fatal viral disease.

(ix) ………….. is the maintenance of chicks for a few weeks after hatching.

Answer: Brooding

Teacher's Note:
a) Brooding lasts for 4 to 6 weeks; incubation is for the eggs.

(x) The rearing of aquatic fauna at commercial level is called …………..

Answer: Aquaculture

Teacher's Note:
a) It includes fishes, prawns, shrimps, crabs and pearl oysters.

4. Answer the followings :

(i) Which caste of honey bees has all sterile members ?

Answer: Workers

Teacher's Note:
a) They are diploid and sterile females.

(ii) To which order of class Insecta do honey bees belong?

Answer: Hymenoptera

Teacher's Note:
a) Silk worms belong to Lepidoptera.

(iii) What is the rearing of honey bees called ?

Answer: Apiculture (bee keeping)

Teacher's Note:
a) The place where bees are reared is the apiary.

(iv) Who decoded the communication language of honey bees ?

Answer: Prof. Karl von Frisch

Teacher's Note:
a) He received the Nobel prize in 1969.

(v) What is the scientific name of Italian honey bee ?

Answer: Apis mellifera

Teacher's Note:
a) Apis indica is the commonly domesticated Indian bee.

(vi) Which insect is the best pollinator?

Answer: Honey bee

Teacher's Note:
a) Bees pollinate Brassica, apple and pear.

(vii) Which caste of honey bees has all haploid members ?

Answer: Drones

Teacher's Note:
a) They develop from unfertilized eggs.

(viii) What are the developmental stages between eggs and adult ?

Answer: Larva (grub) and pupa

Teacher's Note:
a) Honey bee is a holometabolous insect: egg, larva, pupa, adult.

5. Match the insect of column A with the 2 items of column B :

(i) Philosamia ricini

Answer:
A and H: Poor man's silk; feeds on castor leaves
(ii) Antherea paphia - E and F: Tasar silk; feeds on leaves of Saal
(iii) Bombyx mori - D and J: Wholly domesticated; mulberry silk
(iv) Tachardia - C and G: Lac; females are degenerate forms
(v) Antherea assama - B and I: Muga silk; reared in India only

Teacher's Note:
a) Eri silk worm is Philosamia (Attacus) ricini.
b) Muga silk is produced only in Assam, India.

6. Fill in the blanks

(i) _____________ is the oldest method of crop improvement.

Answer: Selection

Teacher's Note:
a) Almost all present crops come from selection by prehistoric humans.

(ii) Mass selection method is useful _____________ pollinated crops.

Answer: in self

Teacher's Note:
a) Self pollinated plants are homozygous and keep the selected traits.

(iii) The self pollinated progenies of homozygous plants forms a _____________.

Answer: pure line

Teacher's Note:
a) Pure line selection starts with a single selected plant.

(iv) _____________ is sudden, stable and heritable change which alters the genotype of an organisms.

Answer: Mutation

Teacher's Note:
a) Mutagens such as X-rays, gamma rays and EMS induce it.

(v) _____________ is the improvement of nutritional quality of crops.

Answer: Biofortification

Teacher's Note:
a) Examples are vitamin A enriched carrot and iron enriched spinach.

7. Fill in the blanks

(i) The part of the plant which is used in tissue culture is called _____________.

Answer: explant

Teacher's Note:
a) It may be a root tip, shoot bud, leaf petiole, anther or embryo.

(ii) _____________ are embryo like structure derived from vegetative cells.

Answer: Embryoids

Teacher's Note:
a) Totipotency makes this possible.

(iii) _____________ promotes root production in callus.

Answer: Auxin

Teacher's Note:
a) Cytokinins initiate shoot formation.

(iv) _____________ are genetic variations present in the cells of callus.

Answer: Somaclonal variations

Teacher's Note:
a) Plants from tissue culture are otherwise genetically identical somaclones.

(v) The first somatic hybrid were obtained by somatic hybridization between ________ and _________.

Answer: Nicotiana glauca and Nicotiana longsdorfii

Teacher's Note:
a) Pomato (potato and tomato) is an intergeneric somatic hybrid.