Bio – war

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Nowadays, microbes are misused as biological weapons. For instance, a single gram of the most virulent strains of weaponized. Smallpox or anthrax could contain 250 million infectious doses.

Under ideal dispersal conditions, about half the people of the entire. World when exposed to these germs could become ill and one-third might die.

Deadly organisms

Even from a very long period, pathogens causing some of the deadliest diseases in men are being used as biological weapons. More than 2,000 years ago, Scythian archers used their arrow heads. Which were dipped in rotting corpses in order to cause panic amongst people.

The tips of arrowhead caused infections. During World war II, papar bags filled with plague infested fleas were employed as biological weapons to kill thousands of people. At that time, well equipped and expensive laboratories were established to mass produce biological weapons.

At present, each and every nation is facing the threat from biological weapons. People affected by the biological war have to suffer throughout their life.

Genetically Modified Organisms (GMO) in biological warfare

Using Molecular biology techniques, new combinations of genes were
attempted to create genetically modified organisms (GMO).

Some of the most lethal agents known to have been tested in biological warfare are anthrax, plague, smallpox and Ebola viruses with viral diseases.

People were aware of the reality that a small group of fanatical terrorists could easily contaminate the country’s air, water and food with lethal pathogens or biological toxins.

Biological warfare

Thus biological warfare introduces issues of pathogenicity, toxicity,
routes of exposure, safety measures and the movement, distribution and persistence of dangerous biological materials in our environment.

In biological warfare strategies, the genetically engineered microorganisms are made to spread into the enemy’s territorial environment, with unpredictable and perhaps catastrophic consequences.

The released dangerous microorganisms ‘upset the balance of nature’.

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Other links 

Plant physiology – photosynthesis and its significance

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BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Green manuring, Mycorrhiza as biofertilizer

---

Benefits from biofertilizers

---

Crop diseases and their control, Rice – Oryza sativa

---

Groundnut or peanut – Arachis hypogea

---

Citrus canker, Tungro disease of rice

---

Biocontrol of insect pests Bacterial pesticides

---

Genetically modified food

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Genetically modified food

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The greater concern in food biotechnology is the integration of both
modern biological knowledge and techniques and current bioengineering principles in food processing and preservation.

Modern biotechnological techniques will have considerable importance in influencing trends in the food market, namely cost, preservation, taste, consistency, colour and above all, health aspects.

Every year more than a million children die and another 3,50,000 go
blind from the effects of vitamin A deficiency. Employing genetic
engineering techniques, Potrykus of Switzerland and Peter Beyer of Germany transferred genes that make carotene in daffodils into Oryza sativa.

Ordinarytechniques of plant breeding do not offer a way to enrich the crop. Extracting carotene genes from daffodils, Potrykus and Beyer had introduced these genes into the soil bacterium.

Agrobacterium tumefaciens, the transgenic agrobacteria were then incubated with rice embryos in plant tissue culture medium. As the bacterium infects the rice cells, they also transfer the genes for making beta carotene.

A number of examples are available where transgenic plants suitable for food processing have been developed.
(i) Tomatoes with elevated sucrose and reduced starch could also be
produced using sucrose phosphate synthase gene.
(ii) Starch content in potatoes could be increased by 20 to 40 per cent by using a bacterial ADP glucose pyrophosphorylase gene (ADP GPPase).
(iii) Vaccines, antibodies and interferons can be consumed directly along with tomato, banana and cucumber.

Edible vaccine

Acute watery diarrhoea is caused by Escherichia coli and Vibrio
cholerae that colonize the small intestine and produce enterotoxin.
Attempts were made to produce transgenic potato tubers that they could still retain vaccines in their tubers, even after the tubers had become 5 per cent soft after boiling. 50 per cent of vaccine was still present in the tubers.

Edible antibodies

Transgenic plants are being looked upon as a source of antibodies.
They can also provide passive immunization by direct application.

Edible interferons

Interferons are the substances made of proteins and are anti-viral in
nature. Scientists have successfully produced transgenic tobacco and maize plants that secrete human interferons . Today, rice crops have been enriched with vitamin A through gene manipulation. Similarly, pulse crop have been tampered with to produce lysine-rich pulse seeds. Such genetically modified food (GMF) are now becoming components of human staple food.

It is hoped that one day genetically engineered plants will have one
or more of these attributes:
i. They will show tolerance against heat, cold, drought or salt.
ii. They are more nutritious.
iii. They can be stored and transported without fear of damage.
iv. They require less fertilizer.
v. They produce chemicals and drugs that are of interest to humans.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Green manuring, Mycorrhiza as biofertilizer

---

Benefits from biofertilizers

---

Crop diseases and their control, Rice – Oryza sativa

---

Groundnut or peanut – Arachis hypogea

---

Citrus canker, Tungro disease of rice

---

Biocontrol of insect pests Bacterial pesticides

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Biocontrol of insect pests

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1. The manufacture of methyl isocynate (MIC) was started in 1980 in
India to make Serin (carbaryl), a powerful pesticide that can kill more
than 100 types of insects attacking 100 different crops.

2. Many of the chemical pesticides, which are used to control several
crop pests also affects the beneficial organisms.

3. They also bring about considerable damages to living organisms
because of their hazardous effects in the environment.

There was an enmasse killing of more than 4,000 people, many animals and plants, when methyl isocyanate (MIC) gas leaked out in the night of 2nd and 3rd December, 1984 from the underground reservoir of Union Carbide Factory at Bhopal.

This is mentioned as Bhopal Tragedy. Many of the people exposed to this poisonous gas are suffering even today.

4. Majority of microorganisms such as viruses, bacteria, fungi,
protozoa and mycoplasma are known to kill insect pests.

The suitable preparations of such microorganisms for control of insects are called as ‘microbial insecticides’. These are non-hazardous, non-phytotoxic and are selective in their action.

They are eco-friendly not responsible for environmental degradation. The most frequently used bio-control agent is Bacillus thuringiensis and Pyrethrum extracted from the inflorescence of Chrysanthemum belonging to Asteraceae.

Bacterial pesticides

B. thuringiensis is a widely distributed bacterium. It is a saprophytic bacterium and can be isolated from soils, litters and dead insects. It is a spore-forming bacterium and produces several toxins such as exotoxins and endotoxins in crystallized forms.

The bacterium is harmful to lepidoptera insects. After infection of spore, larvae are damaged due to the secretion of a single large crystal in the cell. This crystal (toxin) is proteinaceous in nature.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Green manuring, Mycorrhiza as biofertilizer

---

Benefits from biofertilizers

---

Crop diseases and their control, Rice – Oryza sativa

---

Groundnut or peanut – Arachis hypogea

---

Citrus canker, Tungro disease of rice

---

Genetically modified food

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Citrus canker

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Pathogen

Disease due to a bacterium Xanthomonas citri. This bacterium is of bacillus and gram negative type. In India, this is the most commonly prevalent disease during the rains.

Symptoms

The disease affects the leaves, twigs, thorns and fruits. All green
parts and maturing fruits become more or less covered with brown scabby spots surrounded by dark – brown glossy margins.

The lesions may enlarge to a diameter of 3 or 4 mm become raised and rough and turn brown. The bacteria enter through the stomata and wounds and multiply in the cortex to which they are confined.

Control

The infection can be largely prevented by removing the infected branches and spraying the plants with Bordeaux mixture or spraying 3 to 4 times in a season with antibiotic the streptocycline at the rate of 1 gm in 45 liters of water.

Tungro disease of rice

Pathogen

Disease incited by a virus Rice Tungro virus. The virus is transmitted by a leafhopper.

Symptoms

The symptoms appear first on the emerging leaf. They are mild
interveinal chlorosis (loss of chlorophyll), mild mottling and yellowing. Plant shows stunted growth and symptoms appear on the lower leaves. They turn yellow orange, bend downwards and possess dark brown spots.

Transmission of virus

The leafhopper retains infectivity for a short period only and transmits the virus to another plant immediately after feeding on an infected plant.

Biopesticides

Biological agents that are used for control of insects, weeds and
pathogens produced from living organisms are called biopesticides. Microorganisms such as viruses, bacteria, fungi, protozoa and mites may be used as biopesticides.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Green manuring, Mycorrhiza as biofertilizer

---

Benefits from biofertilizers

---

Crop diseases and their control, Rice – Oryza sativa

---

Groundnut or peanut – Arachis hypogea

---

Biocontrol of insect pests Bacterial pesticides

---

Genetically modified food

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Groundnut or peanut – Arachis hypogea

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Tikka disease of groundnut

Pathogen Disease incited by a fungus Cercospora personata.
Systematic position The fungus belongs to class Deuteromycetes.

Symptoms

Lesions appear on the leaves, when the plants are atleast two months old. The symptoms appear in July and continue upto maturity of the plant.

The lesions on the leaves are rounded and 1 to 6 mm in diameter. These spots are dark brown or black and found on both surfaces of the leaf. Yellow border develops around each such leaf spot.

Pathogen

The mycelium of Cercospora personata is brown, septate branched
and slender. Branched haustoria are produced to absorb food materials from the host tissue.

The conidia are long and septate. Each conidiophore produces single conidium at its tip. The spread of the disease takes place by means of conidia which are dispersed by wind.

Control

The disease can be controlled by sanitation and crop rotation. The
use of phosphatic and potassic manures reduce the disease. Sulphur dusting is quite effective. Resistant variety should be sown.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Green manuring, Mycorrhiza as biofertilizer

---

Benefits from biofertilizers

---

Crop diseases and their control, Rice – Oryza sativa

---

Citrus canker, Tungro disease of rice

---

Biocontrol of insect pests Bacterial pesticides

---

Genetically modified food

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Crop diseases and their control

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The diseases in crop plants result in a heavy loss of crop yields and
cause considerable damage to crops year after year. To check the plant diseases, it becomes necessary to know about the cause of the diseases, of the life history of the causal organism and of the meterological conditions which influence the host and parasite interaction.

Control measures may be divided into two main groups – prophylaxis
and disease resistance. Prophylaxis includes the protection of the host from exposure to the pathogen, from infection or from environmental factors favourable to disease development.

Disease – resistance implies the improvement of resistance of the host to infection and to disease development.

SPECIFIC DISEASES

Rice – Oryza sativa
Pathogen Disease incited by a fungus, Pyricularia oryzae.
Name of the disease Blast disease of rice.
Systematic position The fungus belongs to class: Deuteromycetes.

Symptoms

The symptoms are found on the leaf blades, leaf sheaths and rachis.
Characteristic isolated, bluish – green necrotic lesions with a water –
soaked appearance are formed on the leaf – blades.

The lesions are broad in the centre and possess narrow elongations on its top and bottom. The lesion – formation leads to ultimate drying of the leaves, and the seedlings wither and die.

After transplantation, the symptoms appear in the form of necrotic
lesions both on the leaf lamina and the leaf sheaths. The necrotic lesion is spindle shaped grey in the centre and remain surrounded by brown and yellowish zones. The leaves ultimately dry up.

The pathogen

The fungus Pyricularia oryzae when young possesses hyaline and
septate mycelium. On maturity, the colour of mycelium changes to olive brown. Conidia are produced terminally. Each conidium is obpyriform septate with a small basal appendage.

Control measures

The most economic method of control is the cultivation of resistant,
high yielding varieties.

Seed treatment

Immersion of the seeds in 0.2 per cent solution of Kalimat B for 24
hours controlled the disease and promoted the growth of seedlings. The seed protectants such as agrosan, cerasan and spergon have been proved responsible for the control of disease.

Sanitation

Plant debris should be collected and destroyed. The secondary host
plants such as Digitaria marginata should be collected from paddy fields and destroyed.

Spraying and dusting

Blast disease can be controlled effectively by spraying the fungicide,
Bordeaux mixture at least 4 times before and after flowering of the crop. Bordeaux mixture formula is as follows:
Copper sulphate 9 Kgs.
Quick lime 9 Kgs.
Water 250 litres.
The dusting of organomercuric compounds has been suggested for
controlling blast.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Green manuring, Mycorrhiza as biofertilizer

---

Benefits from biofertilizers

 

---

Groundnut or peanut – Arachis hypogea

---

Citrus canker, Tungro disease of rice

---

Biocontrol of insect pests Bacterial pesticides

---

Genetically modified food

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Benefits from biofertilizers

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1. Biofertilizers are easy to produce in abundance and are available
at low cost to the marginal farmers.

2. It increases soil fertility without causing any damage to the soil.

3. Application of biofertilizers increases yield upto 45 per cent and
the left over biofertilizers in the soil increases yield as long as the
biofertilizer remains in the soil up to 3 to 4 years.

4. Azolla, which is a biofertilizer amends the soil with organic matter.
Cyanobacteria in particular secrete growth promoting hormones
like indole 3-acetic acid, indole butyric acid, naphthalene acetic
acid, aminoacids, protein and vitamins to soil.

5. Cyanobacteria grow well both in acidic as well as in alkaline soils.
Since, cyanobacteria are potent neutralizers, they help in the
neutralization of soil. The process of converting untenable, fallow
land to cultivable soil is termed as soil reclamation. Blue green
algae play a vital role in this conversion.

6. Symbiotic nitrogen fixing Rhizobium is a biofertilizer. It adds 50
to 150 Kg of nitrogen to soil per hectare. Azatobacter and
Azospirillum secrete antibiotics which act as biopesticides.

7. Ectotrophic mycorrhiza, which acts as a biofertilizer, increases
the surface area of the roots of host plants, so that more absorption
of nutrients by the roots is made possible.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Green manuring, Mycorrhiza as biofertilizer

---

Crop diseases and their control, Rice – Oryza sativa

---

Groundnut or peanut – Arachis hypogea

---

Citrus canker, Tungro disease of rice

---

Biocontrol of insect pests Bacterial pesticides

---

Genetically modified food

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Green manuring

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Various leguminous plants like Crotalaria juncea, Cassia mimusoides, Glycine max, Indigofera linifolia, Sesbania rostrata, Acacia nilotica, Leucena, Lathyrus and Mucuna are used as green manures.

They accumulate more than 80 Kg of nitrogen per hectare in the soil when grown as green manures. Azolla is an aquatic fern, which contains an endophytic cyanobacterium Anabaena azollae in its leaves.

It is used as a biofertilizer in rice field. Out of six species of Azolla, A. pinnata is widely employed as a successful biofertilizer in Indian rice fields. It adds 30 Kg of nitrogen per hectare where the yield is equivalent to that of urea or ammonium phosphate.

Mycorrhiza as biofertilizer

Mycorrhiza is a root inhabiting fungus found around or inside the
roots of many plants. It increases growth and yield and also provides protection to the roots against edaphic (soil) stresses, pathogen and pests.

Helps in the increased uptake of soil and mineral water solution by the plant root system. It provides many uses for the host plants eg. VAM (Vesicular Arbuscular Mycorrhiza) fungi. Mycorrhiza is of two types.

a. Ectotrophic mycorrhiza, which are found only outside the surface
of roots of plants. eg. Basidiomycetous fungi.

b. Endotrophic mycorrhiza, which are found inside the roots, in the
intercellular spaces and even inside the cell (intra and intercellular)
eg. VAM fungi.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Genetic engineering, Improved varieties, Role of biofertilizers

---

Benefits from biofertilizers

---

Crop diseases and their control, Rice – Oryza sativa

---

Groundnut or peanut – Arachis hypogea

---

Citrus canker, Tungro disease of rice

---

Biocontrol of insect pests Bacterial pesticides

---

Genetically modified food

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Genetic engineering

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Genetic engineering will enable the plant or animal breeder to select the particular gene from one plant and then place the same gene into another plant for it to express its desired character.

Today, genetic engineering is widely employed as a tool in modern crop improvements.

Recombinant DNA technology, popularly termed ‘gene cloning’ or ‘genetic engineering’ offer unlimited opportunities for creating new combination of genes that at the moment do not exist under natural conditions.

Genetic engineering can be defined as the formation of new combinations of heritable material by the insertion of foreign nucleic acid molecule from other sources.

The foreign genes are generally incorporated into a host organism
either through a bacterial plasmid or a virus, which acts as vectors (vehicular traffic). Genes are compared to biological software and are the programs that drive the growth development and functioning of an organism.

By changing the software in a precise and controlled manner, it becomes possible to produce desired changes in the characteristics of the organisms.

eg. E. coli is made to produce human insulin by introduction of human insulin producing gene into bacterial plasmid.

Genetic engineering is a tool used in modern crop improvement
programs. Its objective is to isolate and introduce a gene or genes into a crop plant that normally does not possess them.

Addition of genes or DNA (foreign genes) from one plant or a microbe to another plant is called transgenic plant.

Herbicide resistance, saline resistance, altered flower colour, improved protein quality and protection against viral infection are few examples of recently formed transgenic higher plants by using this technology eg. tobacco, tomato, potato, sunflower and apple.

Improved varieties

Improvement of a crop lies in its genetic make up and the environment in which it grows and interacts. An improved variety is one that is superior to other existing varieties in one or few characters. It may show high yield than other varieties, early maturity, disease and pest resistance.

A new improved variety is developed by continuous breeding experiments as described above under various methods. By making use of modern technologies, like biotechnology, tissue culture and conventional breeding methods new improved crops are obtained with desirable characters that suits well to the existing environment without polluting or altering it in any way.

In order to release a newly created variety it takes nearly 12 years involving extensive field trials, naming and multiplication.

Role of biofertilizers

Extensive use of fertilizers and chemical pesticides had resulted in
soil and water pollution. Fossil fuels such as petrol and coal are used in the manufacture of fertilizers and pesticides.

To reduce pollution and over usage of our non-renewable resources like coal, petroleum, etc., an alternative method has been successfully developed to safeguard natural resources.

To maintain soil fertility and soil improvement, fertilizers of biological origin called biofertilizers have been developed. Artificial inoculation of rice and other crop fields with cyanobacteria (Anabaena, Calothrix, Gleocapsa, Lyngbya, Nostoc, Oscillatoria, Scytonema) has attracted much attention to increase fertility in several countries.

The term ‘biofertilizer’ denotes all the nutrient inputs of biological origin for plant growth. Biological origin refers to microbes producing nitrogen compounds. Bacteria and cyanobacteria are known to fix atmospheric nitrogen and are known as biofertilizers.

Nitrogen fixing bacteria like Azotobacter, Bacillus and Rhizobium increased the crop yield to 20%. Pseudomonas striata are used as seed inoculants as biofertilizer coats for cereals.

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Other links 

Plant physiology – photosynthesis and its significance

---

BIOLOGY IN HUMAN WELFARE Introduction & Food production

---

Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

---

Polyploid breeding, Mutation breeding, Breeding for disease resistance

---

Green manuring, Mycorrhiza as biofertilizer

---

Benefits from biofertilizers

---

Crop diseases and their control, Rice – Oryza sativa

---

Groundnut or peanut – Arachis hypogea

---

Citrus canker, Tungro disease of rice

---

Biocontrol of insect pests Bacterial pesticides

---

Genetically modified food

---

Bio war, Genetically Modified Organisms (GMO) in biological warfare

---

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

---

Sustainable agriculture

---

Medicinal plants including microbes

---

Commonly Available Medicinal Plants

---

Microbes in medicine

---

Economic importance of Food plant Rice

---

Oil plant Groundnut Economic importance

---

Fibre plant – Cotton Economic importance

---

Timber yielding plant Teak Economic importance

---

Polyploid breeding

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The source for plant breeding is variations in plants.. Heritable and
desirable variations occur in nature by mutation, polyploidy, recombination and chromosomal aberrations. A diploid plant has two sets of chromosomes but any organism in which the number of sets of chromosome is doubled is called a polyploid.

When chromosome number is doubled by itself in the same plant, it
is called autopolyploidy. For example, three sets of chromosomes i.e. a triploid condition in sugar beats, apples and pear has resulted in the increase in vigour and fruit size, large root size, large leaves, flower, more seeds and sugar content in them. Seedless tomato, apple, watermelon and orange are autopolyploids.

Polyploidy can be induced by the use of colchicine to double the
chromosome number. Allopolyploids are produced by multiplication of chromosome sets that are initially derived from two different species.
eg. Triticum × Secale gives Triticale.

The haploid individual plant will have only one set of chromosome.
Through the technique of anther and ovary culture, haploid plants can be modified to diploid ones by doubling their chromosomes.

Variations that are brought forth through plant tissue culture are called somoclonal variation. eg. disease resistant potato and rust resistant wheat.

Varieties of short duration sugarcanes are produced by polyploid breeding.

Mutation breeding

Radiation induces mutation to develop new variety of crops. Now
with newer and more powerful sources of radiations (UV shortwave, Xray, Alpha, Beta, Gamma waves) and many chemicals (mutagens) eg. Caesium, ethyl methane sulfonate, nitromethyl urea), we can increase the rates of mutation eg. Triple gene dwarf wheat with increase in yield and height. Atomita 2-rice with saline tolerance and pest resistance, groundnuts with thick shells are products of breeding methods through induced mutation.

Breeding for disease resistance

Many crop plants suffer from several diseases caused by pathogens
such as bacteria, fungi, viruses, nematodes, protozoa and mycoplasma. In vegetatively propagated plants like potato, cassava, sugarcane and dahlia, viral pathogens are transmitted through their roots, tubers, bulbs and rhizomes.

Disease free plants are obtained by shoot apical meristem culture technique. Plants raised through tissue culture are free from pathogens, which are widely cultivated.

Whenever, a trait that shows disease resistance in a plant is observed, the best way to transfer that trait to other useful crop is by the method of backcross. Repeated back crosses are attempted with the parent crop with more desirable characters and such a crop is known as recurrent parent.

For example, A is a non-recurrent parent and B* is a recurrent parent with desirable trait.

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Other links 

Plant physiology – photosynthesis and its significance

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BIOLOGY IN HUMAN WELFARE Introduction & Food production

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Aims of plant breeding

---

Aspects of plant breeding and Types

---

Hybridization in plant breeding

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Genetic engineering, Improved varieties, Role of biofertilizers

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Green manuring, Mycorrhiza as biofertilizer

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Benefits from biofertilizers

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Crop diseases and their control, Rice – Oryza sativa

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Groundnut or peanut – Arachis hypogea

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Citrus canker, Tungro disease of rice

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Biocontrol of insect pests Bacterial pesticides

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Genetically modified food

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Bio war, Genetically Modified Organisms (GMO) in biological warfare

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Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

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Sustainable agriculture

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Medicinal plants including microbes

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Commonly Available Medicinal Plants

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Microbes in medicine

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Economic importance of Food plant Rice

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Oil plant Groundnut Economic importance

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Fibre plant – Cotton Economic importance

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Timber yielding plant Teak Economic importance

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