Concept-

• Plant breeding as technology has helped increase yields to a very large extent.
• The development of several high-yielding varieties of wheat and rice in the mid-1960s resulted from various plant breeding techniques, leading to a dramatic increase in food production in our country. This phase is often referred to as the Green Revolution.
• Green Revolution was responsible for our country to not merely meet the national requirements in food production but also helped us even to export it.
• The green revolution was dependent to a large extent on plant breeding techniques for the development of high-yielding and disease-resistant varieties in wheat, rice, maize, etc.

Explanation-

• During the period 1960 to 2000, wheat production increased from 11 million tonnes to 75 million tonnes.
• This was due to the development of semi-dwarf varieties of wheat and rice.
• Nobel laureate Norman E. Borlaug, at International Centre for Wheat and Maize Improvement in Mexico, developed semi-dwarf wheat.
• In 1963, several varieties such as Sonalika and Kalyan Sona, which were high yielding and disease resistant, were introduced all over the wheat-growing belt of India.

Therefore the scientist who developed semi-dwarf varieties of wheat in Mexico is Norman E. Borlaug.

Important Points

• Norman E. Borlaug is called the father of the Green Revolution worldwide.
• Dr M.S. Swaminathan is the father of the green revolution in India.

Additional Information

Watson and Crick

• Watson & crick proposed the double-helical structure of DNA.
• While proposing the double-helical structure for DNA, Watson and Crick had immediately proposed a DNA replication scheme.
• ‘‘It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material’’ (Watson and Crick, 1953).

Concept-

• Animal husbandry is the agricultural practise of breeding and raising livestock.
• Animal husbandry deals with the care and breeding of livestock like buffaloes, cows, pigs, horses, cattle, sheep, camels, goats, etc., that are useful to humans.
• Since time immemorial, animals like bees, silk-worm, prawns, crabs, fishes, birds, pigs, cattle, sheep, and camels have been used by humans for products like milk, eggs, meat, wool, silk, honey, etc.
• It is estimated that more than 70 per cent of the world's livestock population is in India and China. 

Explanation-

• Bee-keeping or apiculture is the maintenance of hives of honeybees for the production of honey.
• It has been an age-old cottage industry.
• Honey is a food of high nutritive value and also finds use in the indigenous systems of medicine.
• Honeybee also produces beeswax, which finds many uses in industry, such as in the preparation of cosmetics and polishes of various kinds.
• There are several species of honeybees that can be reared. Of these, the most common species is Apis indica.
• Along with Apis indica, the other local varieties of bees used in bee-keeping for commercial honey production are Apis cerana Indica, commonly known as the Indian bee, A. dorsata, the rock bee and A. florae, the little bee.

Therefore Apis indica is used in Bee-keeping.

Important Points

The following points are important for successful bee-keeping

• Knowledge of the nature and habits of bees.
• Selection of a suitable location for keeping the beehives.
• Catching and hiving of swarms (group of bees).
• Management of beehives during different seasons.
• Handling and collection of honey and of beeswax.
• Bees are the pollinators of many of our crop species such as sunflower, Brassica, apple, and pear.
• Keeping beehives in crop fields during the flowering period increases pollination efficiency and improves the yield–beneficial both from the point of view of crop yield and honey yield. 

Additional Information

• Hilsa is a marine fish.
• Sonalika is a variety of semi-dwarf wheat.

Concept-

• The breeding of animals is an important aspect of animal husbandry.
• Animal breeding aims at increasing the yield of animals and improving the desirable qualities of the produce.
• MOET technology has been demonstrated for cattle, sheep, rabbits, buffaloes, mares, etc.
• High milk-yielding breeds of females and high quality (lean meat with less lipid) meat-yielding bulls have been bred successfully to increase herd size in a short time.

Explanation-

• Multiple Ovulation Embryo Transfer Technology (MOET) is one such program for herd improvement.
• In this method, a cow is administered hormones, with FSH-like activity, to induce follicular maturation and superovulation – instead of one egg, which they normally yield per cycle, they produce 6-8 eggs.
• The animal is either mated with an elite bull or artificially inseminated.
• The fertilized eggs at 8–32 cells stages, are recovered non-surgically and transferred to surrogate mothers.
• The genetic mother is available for another round of superovulation.

Therefore the technique used to improve the chances of a successful production of hybrids is MOET.

Additional Information

Inbreeding

• Inbreeding refers to the mating of more closely related individuals within the same breed for 4- 6 generations.
• The breeding strategy is as follows – superior males and superior females of the same breed are identified and mated in pairs.

Out-crossing

• This is the practice of mating of animals within the same breed, but having no common ancestors on either side of their pedigree up to 4-6 generations.
• The offspring of such a mating is known as an out-cross.
• It is the best breeding method for animals that are below average in productivity in milk production, growth rate in beef cattle, etc. 

The correct answer is Jaya.

Explanation: 

• In the mid-1960s Green revolution started in India which led to the introduction of several high-yielding hybrid varieties of different crops like Wheat & Rice.
• The green revolution led to a dramatic increase in food production in our country.
• Jaya & Ratna are semi-dwarf hybrid varieties of rice developed in India during the Green revolution. Due to these hybrid varieties production of Rice increased from 35 million tonnes to 89.5 million tonnes.
• The green revolution helped India to become Self-reliant in Agriculture.

Additional Information

• Semi-dwarf rice is a hybrid rice variety that has a higher yield than normal rice. It was introduced in India in the year 1966.
• Himagiri is a hybrid variety of Wheat that provides resistance to diseases like Leaf and stripe rust, hill bunt.
• Pusa swarnim is a hybrid variety of Brassica that is resistant to white rust disease.​ 

Important Points

• Professor M.S Swaminathan is known as the father of the green revolution in India

Concept:

• Plant breeding is the intentional manipulation of plant species to create desirable varieties that are better suited for cultivation, can give better yield and are disease resistant.
• Several bacterial, fungal or viral pathogens affect the crop plants, reducing their yield.
• Crop losses can sum up to 20-30% or even total loss.
• Thus, development of disease-resistant cultivars are essential to enhance food production.
• Resistance of host plant refers to the ability of the plant to prevent the infection and this is determined by the genetic constituent of the plant.
• Study of the pathogen and its mode of transmission precedes the breeding process.

Key Points

• Breeding can be achieved by conventional methods or mutation breeding.
• The steps for breeding are:
  1. Screening germplasm for resistance sources
  2. Hybridization of selected parents
  3. Selection and evaluation of the hybrids
  4. Testing and release of new varieties

Some Resistant Varieties:

Explanation:

• From the above table we can find the correct match of the crop variety and the disease it is resistant to:
  • Karan rai - White rust
  • Pusa Komal - Bacterial blight
  • Himgiri - Hill bunt
  • Pusa Sadabahar - Leaf Curl

Therefore, the option (2): (A) - (IV), (B) - (I), (C) - (II), (D) - (III) is the correct answer.

The correct answer (wrong statement) is Bacteria is used in preparation of breads and cakes.

Explanation:

Statement 1 is correct.

• Herbivores animals consume grass and other plant material. Plants contain cellulose, which is difficult to digest.
• When a herbivore swallows grass, the chewed grass first enters the stomach known as the rumen.
• The rumen contains a salty fluid as well as bacteria that help in the breakdown of cellulose.
• Herbivorous animals can digest cellulose because bacteria in their caecum help in the breakdown of cellulose.

Statement 2 is correct.

• Bacteria are utilised in the production of pharmaceuticals.
• Streptomycin, tetracycline, and erythromycin are examples of well-known antibiotics derived from fungi and bacteria.
• Antibiotics are produced by growing specific microbes and are used to cure a variety of diseases.
• Antibiotics are even mixed with livestock and poultry feed to prevent microbial infection in animals. They are also used to control various plant diseases.
• They are used in agriculture to boost soil fertility by fixing nitrogen.

Statement 3 is incorrect.

• Yeast is a microorganism is used in the preparation of bread and cakes.
• Bread is made by fermentation by Saccharomyces cerevisiae or commonly called baker's yeast.
• Yeast reproduces rapidly and produces carbon dioxide during respiration. Bubbles of the gas fill the dough and increase its volume.
• This is the basis of the use of yeast in the baking industry for making bread, pastries and cakes.
• Curd contains a variety of microorganisms. Lactobacillus is a bacterium that promotes the formation of curd. It multiplies in milk and ferments it to make curd. Bacteria are also involved in the production of cheese, pickles, and a variety of other foods.

Statement 4 is correct.

• Anaerobic digestion is a process in which bacteria break down organic matter in the absence of oxygen, such as animal dung, wastewater biosolids, and food waste. Anaerobic digestion for biogas production occurs in a sealed tank known as a reactor.
• In biogas plant, methanobacterium anaerobically breaks down organic matter to produce CO₂ and H₂O.

Bioprocess/Fermentation is a process which utilizes complete living cells or their segments (e.g., microscopic organisms, chemicals, chloroplasts) to get desired items.

• In practice, many bioprocessing techniques will be used industrially because they are the only practical way in which a specific product can be made (e.g. vaccines, antibiotics).
• The very beginnings of fermentation technology, or as it is now better recognised, bioprocess technology, were derived in part from the use of microorganisms for the production of foods such as cheeses, yoghurts, sauerkraut, fermented pickles and sausages, soya sauce and other Oriental products, and beverages such as beers, wines and derived spirits.
• Process of Fermentation includes the use of microorganisms, like yeast and bacteria for the production of enzymes.
• Along with aerobic respiration, fermentation is a method to extract energy from molecules. This method is the only one common to all bacteria and eukaryotes. It is therefore considered the oldest metabolic pathway, suitable for primeval environments - before plant life on Earth, that is, before oxygen in the atmosphere.
• Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it to curd.
• The dough, which is used for making foods such as dosa and idli, is also fermented by bacteria. The puffed-up appearance of dough is due to the production of CO2 gas.
• Similarly the dough, which is used for making bread, is fermented using baker’s yeast (Saccharomyces cerevisiae). A number of traditional drinks and foods are also made by fermentation by the microbes.

Key Points

• Methanogenic bacteria are those that grow anaerobically on cellulosic material and produce biogas.
• Biogas contains gases like methane (CH₄), carbon dioxide (CO₂) and hydrogen (H₂).
• Methanogenic bacteria are found in:
  • Rumen of cattle - They help in digesting the cellulose and give nutrition to the cattle.
  • Biogas plant - They are present in cow dung, which goes into the biogas plant for biogas production.
  • Anaerobic sludge - As these bacteria grow anaerobically, they can be found in anaerobic sludge that is produced during biological wastewater treatment.
• Activated sludge is produced from flocs of aerobic bacteria during sewage treatment.
• Therefore, methanogenic bacteria is not present in activated sludge.

Additional InformationSewage Treatment Process:

1. ​Primary Treatment -
   • Floating debris is removed by sequential filtration.
   • The grit (soil and small pebbles) are removed by sedimentation.
   • The solids settle as primary sludge and the supernatant as effluent.
   • The effluent moves from primary settling tank to large aeration tanks for secondary treatment.
2. Secondary/Biological Treatment -
   • The effluent is continuously agitated mechanically and air is pumped into it.
   • This allows vigorous growth of aerobic microbes into flocs.
   • These microbes use up most of the organic matter for their growth.
   • This reduces the BOD (biological oxygen demand) of the effluent.
   • Effluent is then passed into a settling tank, where the bacterial flocs sediment to form the activated sludge.
   • Most of the activated sludge is moved into large tanks called anaerobic sludge digesters, and the rest is used as inoculum in the aeration tanks.
   • Next, the anaerobic bacteria digest the other bacteria and fungi in the sludge.
   • These are mostly methanogenic bacteria, which produce biogas.
   • The effluent is then discharged into water bodies.

Key Points

• Microbes play an important role for the production of industrial products.
• They are used for fermented beverages, antibiotics, bioactive molecules as well as food products like cheese.
• Microbes may include bacteria as well as fungi.
• Monascus pupureus is a type of yeast that is used to produce statins.
• Statins are blood cholesterol-lowering agents.
• It can induce competitive inhibition of the enzyme responsible for synthesis of cholesterol.

Additional Information

• Cyclosporin A -
  • ​It is produced from the fungus Trichoderma polysporum.
  • It is used as an immunosuppressive agent in organ transplant patients.
• Streptokinase -
  • ​It is produced from the bacterium Streptococcus.
  • It is used as a 'clot-buster' to remove unwanted blood clots in the blood vessels.
  • It is particularly useful in patients who have undergone myocardial infarction leading to heart attack.
• Acetic acid -
  • ​It is industrially produced from the bacterium Acetobacter aceti.

Concept:

• 'Biofertilizer' is a substance which contains living microorganism which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. Biofertilizers are not fertilizers.
• Fertilizers directly increase soil fertility by adding nutrients. Biofertilizers add nutrients through the natural processes of fixing atmospheric nitrogen, solubilizing Phosphorus, and stimulating plant growth through the synthesis of growth-promoting substances.

Explanation:

• The major sources of Biofertilizers include Algae, Fungi, Cyano-bacteria & pteridophyte
• Atmospheric nitrogen cannot be absorbed directly by the plants so it is first converted into stable compound ammonia (NH3) in the roots, with the help of bacteria present in the biofertilizers.
• N2 → N2H2 → N2H4 → 2NH3

​ (nitrogen) (dimide) (hydrazine) (ammonia)

• Some of the biofertilizers include Rhizobium, Mycorhizza, Azolla

Important Points 

• In leguminous plants, Rhizobium bacteria helps in fixing the atmospheric nitrogen
• Azolla pinnata serves as a great biofertilizer for paddy crops (rice). It increases the nutrient uptake and grain yield of rice.
• Mycorrhiza is a symbiotic association of a fungus with a root system.

Additional Information

• Bacillus thuringiensis is used as a biopesticide. It is a vector used for preparing genetically modified organisms that are specific pest resistant. Crop prepared using Bacillus thuringiensis is BT Cotton for control of pest Bollworm.