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State Board · Class 12 · Biology

Lesson 11: Enhancement of Food Production

7 concepts · 56 practice questions with answers · Free to read

This lesson is also in: मराठी

Plant breeding and the Green Revolution

Link to Std 9–10

Last lesson covered disease and health; here we learn how living things help raise food production for a growing population.

From daily life

A farmer keeps the best grains as next season's seed — the start of selection.

Simple definition

Plant breeding = scientific method of creating new varieties with useful traits. A variety = crop line with uniform traits.

Plant breedingPlant breedingCollectiongermplasmSelectionbest plantsHybridisationcrossingTestingtest & releaseSteps: variation → selection → hybridisation → selection → testing → seedGreen Revolution: Norman Borlaug (Nobel 1970), dwarf wheatIndia: Sonalika, Kalyan Sona (wheat); IR-8, Jaya (rice)Disease resistance: Himgiri (wheat — rust), Pusa Swarnim (mustard)Pusa Shubra (cauliflower), Pusa Sawani (okra — virus resistant)Aims: yield, disease/pest resistance, quality, stress toleranceGermplasm collection = gene bank

In the figure : Breeding steps and varieties.

Rule 1 : Steps of plant breeding — (1) Collect variation — wild/local lines; germplasm (gene bank). (2) Selection — plants with wanted traits. (3) Hybridisation — cross two parents; combine traits. (4) Selection again among hybrids. (5) Testing — many sites, many seasons. (6) Release — multiply seed for farmers. Aims: higher yield, disease/pest resistance, better quality, drought/salt tolerance.

  • Easy : Germplasm = gene bank.
  • Medium : Selection twice.
  • Exam-type (CET) : No variety without testing.

Rule 2 : Green Revolution and varieties — Norman Borlaug (Nobel 1970) developed dwarf, high-yield wheat; in India M. S. Swaminathan helped adopt them. Wheat: Sonalika, Kalyan Sona; rice: IR-8, Jaya. Resistant: Himgiri (wheat — rust), Pusa Swarnim (mustard — fungal), Pusa Shubra (cauliflower), Pusa Sawani (okra — yellow mosaic virus). Being dwarf, plants do not fall over even with heavy grain.

  • Easy : Borlaug = dwarf wheat.
  • Medium : Pusa Sawani = okra.
  • Exam-type (CET) : Himgiri = rust-resistant.
Remember

Collect → select → cross → test → release.

Common mistake and CET trap

‘Sonalika is a rice variety’ is wrong (wheat). Trap: ‘Pusa Sawani is mustard’ is wrong (okra).

Shortcut

Memory clue : "Sonalika, Kalyan Sona = golden wheat".

Spot the difference

CropVariety
WheatSonalika, Himgiri
RiceIR-8, Jaya
OkraPusa Sawani

Practice questions

Easy
  1. 1What is germplasm?
  2. 2Father of Green Revolution?
  3. 3Benefit of dwarf wheat?
Medium
  1. 4Himgiri resists?
  2. 5Pusa Shubra is?
  3. 6Rice varieties?
Challenging
  1. 7Hybridisation means?
  2. 8Why testing?
Show answers (try them yourself first)
  1. 1Gene bank / genetic diversity.
  2. 2Norman Borlaug.
  3. 3Plants do not lodge.
  4. 4Rust disease.
  5. 5A cauliflower variety.
  6. 6IR-8, Jaya.
  7. 7Crossing two parents.
  8. 8To confirm stable performance.

Mutation, polyploidy and tissue culture

From daily life

A single leaf in a pot can sprout a new plant — a cell's ability to rebuild a whole plant.

Simple definition

Totipotency = ability of a single cell to form a whole organism. Tissue culture = growing plants from cells/tissues on artificial medium.

Modern methodsMutation, polyploidy, tissue cultureMutationgene changePolyploidyextra chromosome setsTissue cultureplant from a cellMutation breeding: γ-rays/chemicals; e.g. disease-resistant mungColchicine: polyploidy (e.g. triticale = wheat × rye)Totipotency: whole plant from one cellMedium: MS — nutrients, sucrose, auxin, cytokininCallus → organogenesis → plantlet → hardening → fieldMeristem culture: disease-free plants; micropropagation: rapid multiplicationSomaclones: identical plants; haploids: anther culture

In the figure : Mutation, polyploidy, tissue culture.

Rule 1 : Mutation and polyploidy — Mutation breeding: γ-rays or chemicals change genes; useful changes are selected (e.g. disease-resistant lines). Polyploidy: more chromosome sets (with colchicine) — bigger fruits/grains. E.g. Triticale = wheat × rye (wheat quality + rye hardiness). Haploid plants through anther culture; doubled to give homozygous pure lines.

  • Easy : Colchicine = polyploidy.
  • Medium : Triticale = wheat × rye.
  • Exam-type (CET) : γ-rays = mutation.

Rule 2 : Tissue culture — Explant (leaf/root/shoot tip) → sterile MS medium (mineral salts, sucrose, auxin, cytokinin) → callus (undifferentiated cells) → organogenesis (roots/shoots) → plantlet → hardening → field. More auxin ⇒ roots; more cytokinin ⇒ shoots. Uses: micropropagation (rapid), meristem culture (virus-free plants), somaclones (identical), all-year, small space. E.g. banana, sugarcane, orchid, potato.

  • Easy : Callus = undifferentiated.
  • Medium : Meristem = virus-free.
  • Exam-type (CET) : Auxin → roots.
Remember

Auxin → anchor roots; cytokinin → shoots.

Common mistake and CET trap

‘Callus is differentiated’ is wrong. Trap: ‘colchicine mutates genes’ is wrong (doubles chromosome sets).

Shortcut

Memory clue : "Totipotent = total potential".

Spot the difference

MethodUse
Meristem cultureVirus-free plant
ColchicinePolyploidy
Anther cultureHaploid

Practice questions

Easy
  1. 1Totipotency?
  2. 2What is callus?
  3. 3High auxin gives?
Medium
  1. 4Benefit of meristem culture?
  2. 5Triticale is?
  3. 6Colchicine used for?
Challenging
  1. 7What is hardening?
  2. 8MS medium?
Show answers (try them yourself first)
  1. 1Whole plant from one cell.
  2. 2Mass of undifferentiated cells.
  3. 3Roots.
  4. 4Virus-free plants.
  5. 5Wheat × rye.
  6. 6Polyploidy.
  7. 7Acclimatising plantlets outdoors.
  8. 8Murashige–Skoog nutrient medium.

SCP and biofortification

From daily life

Microbes in curd and dosa batter are part of food — some microbes become protein food directly.

Simple definition

SCP (single-cell protein) = protein-rich food obtained from microbes. Biofortification = increasing nutrient content of crops.

Food nutritionSCP and biofortificationSCPsingle-cell proteinBiofortifiednutrient-rich cropsSCP: Spirulina, Chlorella, Aspergillus, Saccharomyces, MethylophilusMerits: fast growth, 50–60% protein, grows on wasteMicrobes make protein much faster than farm animalsBiofortification: raise protein, vitamins, mineralse.g. Atlas 66 (wheat — protein), iron-rich rice, vitamin A carrotAim: reduce hidden hunger (micronutrient deficiency)Methods: breeding, genetic engineering, soil enrichment

In the figure : SCP and biofortification.

Rule 1 : Single Cell Protein — Microbes: Spirulina (alga), Chlorella, Aspergillus, Saccharomyces, Methylophilus. Merits: quick growth, 50–60% protein, uses waste (potato-processing waste, straw) as medium, small space, eco-friendly. Limits: safety testing, cost, taste. Uses: human food supplement, animal feed.

  • Easy : Spirulina = algal SCP.
  • Medium : Protein 50–60%.
  • Exam-type (CET) : Grows on waste.

Rule 2 : Biofortification — Raise protein, vitamins, minerals in crops by breeding or genetic engineering. E.g. Atlas 66 (high-protein wheat), iron-rich rice/pearl millet, vitamin A-rich carrot, spinach, pumpkin. Aim: reduce hidden hunger (micronutrient deficiency despite full stomach); helps malnourished children. Methods: conventional breeding, genetic engineering (e.g. golden rice).

  • Easy : Atlas 66 = protein.
  • Medium : Hidden hunger.
  • Exam-type (CET) : Golden rice = vitamin A.
Remember

SCP = tiny protein factories.

Common mistake and CET trap

‘SCP is protein from one animal’ is wrong. Trap: ‘biofortification = using fertilisers’ is wrong.

Shortcut

Memory clue : "Bio-FORTify = fortress of nutrients in crops".

Spot the difference

ConceptExample
SCPSpirulina
BiofortifiedAtlas 66

Practice questions

Easy
  1. 1SCP stands for?
  2. 2An SCP organism?
  3. 3Protein % in SCP?
Medium
  1. 4Atlas 66 is?
  2. 5Hidden hunger?
  3. 6Golden rice rich in?
Challenging
  1. 7SCP grows on?
  2. 8A biofortification method?
Show answers (try them yourself first)
  1. 1Single Cell Protein.
  2. 2Spirulina.
  3. 3About 50–60%.
  4. 4High-protein wheat.
  5. 5Micronutrient deficiency.
  6. 6Vitamin A.
  7. 7Waste materials.
  8. 8Breeding / genetic engineering.

Animal husbandry and allied trades

From daily life

Packet milk, a breakfast egg, honey on bread — all from animal husbandry.

Simple definition

Animal husbandry = care of animals — feed, shelter, breeding, health. A breed = group of animals with uniform traits.

Animal husbandryAnimal husbandryDairymilkPoultryeggs/meatApiculturehoneyFisheriesfishDairy: Sahiwal, Gir (indigenous); Jersey, Holstein (exotic); Murrah (buffalo)Poultry: Leghorn (best layer), Rhode Island RedApiculture: Apis cerana indica; honey, wax; aids pollinationFisheries: fresh/marine; rohu, catla, pomfret; Blue RevolutionBreeding: inbreeding, outcrossing, cross-breeding (Hisardale)AI = artificial insemination; MOET = many embryos; transferWhite Revolution (Operation Flood): Verghese Kurien

In the figure : Dairy, poultry, apiculture, fisheries.

Rule 1 : Dairy, poultry, bees and fish — Dairy: indigenous — Sahiwal, Gir; exotic — Jersey, Holstein; buffalo — Murrah; White Revolution (Operation Flood): Verghese Kurien. Poultry: Leghorn (best layer), Rhode Island Red; eggs and meat. Apiculture: Apis cerana indica; honey, wax; improves pollination; hive management. Fisheries: freshwater (rohu, catla) and marine (pomfret, mackerel); Blue Revolution.

  • Easy : Kurien = White Revolution.
  • Medium : Leghorn = eggs.
  • Exam-type (CET) : Bees aid pollination.

Rule 2 : Breeding, AI and MOET — Inbreeding: closely related mates; pure traits, but inbreeding depression. Outcrossing: unrelated animals of the same breed; cross-breeding: two different breeds — e.g. Hisardale (Bikaneri ewe × Merino ram). AI (artificial insemination): frozen semen of a superior male used for many females. MOET (Multiple Ovulation Embryo Transfer): hormones trigger many eggs, fertilised, embryos placed in other females; more calves from a superior cow.

  • Easy : Hisardale = cross-breed.
  • Medium : AI = frozen semen.
  • Exam-type (CET) : MOET = embryo transfer.
Remember

MOET = many eggs, many calves.

Common mistake and CET trap

‘Jersey is indigenous’ is wrong (exotic). Trap: ‘AI is fertilisation outside the body’ is wrong (semen introduced into female).

Shortcut

Memory clue : "Kurien → milk; blue → fish".

Spot the difference

BreedingMeaning
InbreedingRelated mates
OutcrossingUnrelated, same breed
Cross-breedingDifferent breeds

Practice questions

Easy
  1. 1An indigenous cow breed?
  2. 2A buffalo breed?
  3. 3Best layer?
Medium
  1. 4Leader of White Revolution?
  2. 5Indian bee species?
  3. 6Hisardale is?
Challenging
  1. 7AI means?
  2. 8MOET gives?
Show answers (try them yourself first)
  1. 1Sahiwal / Gir.
  2. 2Murrah.
  3. 3Leghorn.
  4. 4Verghese Kurien.
  5. 5Apis cerana indica.
  6. 6Bikaneri ewe × Merino ram.
  7. 7Artificial insemination.
  8. 8Many embryos from one female.

Industrial microbes

From daily life

Curd, idli batter and rising bread — everyday microbial industries.

Simple definition

Fermentation = microbes convert materials into useful products. BOD = oxygen needed to break down organic matter in water.

Microbial industryMicrobes in industryFermentationproductsAntibioticdrugsSewagewaste waterCurd: Lactobacillus (lactic acid); bread/idli: SaccharomycesSwiss cheese: Propionibacterium (CO₂ holes)Penicillin: Penicillium notatum; streptokinase: StreptococcusCyclosporin A: Trichoderma; statins: Monascus (cholesterol)Citric acid: Aspergillus niger; acetic acid: AcetobacterSewage: primary (filtering) → secondary (biological) → tertiary; low BODBiogas: Methanobacterium; methane 50–70%; cattle dung + waste

In the figure : Industrial microbes.

Rule 1 : Foods, drugs, chemicals — Curd: Lactobacillus turns lactose into lactic acid. Idli/dosa/bread: Saccharomyces ⇒ CO₂ ⇒ rising. Swiss cheese: Propionibacterium (CO₂ holes). Penicillin: Penicillium notatum (Fleming). Streptokinase: Streptococcus (dissolves blood clots). Cyclosporin A: Trichoderma (immunosuppressant in transplants). Statins: Monascus (lowers cholesterol). Citric acid: Aspergillus niger; acetic acid: Acetobacter; lactic acid: Lactobacillus. Beverages and biodiesel also by fermentation.

  • Easy : Penicillin: Penicillium.
  • Medium : Statin: Monascus.
  • Exam-type (CET) : Citric: Aspergillus.

Rule 2 : How fermentation is used — A fermenter (bioreactor) controls temperature, pH, oxygen; selected microbes and nutrient medium. The product is separated and purified (downstream processing). Merits: fast, cheap, renewable raw material. E.g. antibiotics, enzymes, organic acids, lipase (detergents), pectinase (clearing juice).

  • Easy : Fermenter = controlled tank.
  • Medium : Downstream = purification.
  • Exam-type (CET) : Lipase = detergents.
Remember

Fleming → Penicillium, a fungus.

Common mistake and CET trap

‘Penicillin from Streptococcus’ is wrong. Trap: ‘statins from Aspergillus’ is wrong (Monascus).

Shortcut

Memory clue : "Fleming → Penicillium, a fungus".

Spot the difference

ProductMicrobe
PenicillinPenicillium
Citric acidAspergillus niger
StreptokinaseStreptococcus

Practice questions

Easy
  1. 1Curd bacterium?
  2. 2Holes in Swiss cheese due to?
  3. 3Penicillin source?
Medium
  1. 4Streptokinase use?
  2. 5Statin source?
  3. 6Cyclosporin A source?
Challenging
  1. 7Citric acid made by?
  2. 8Fermenter is?
Show answers (try them yourself first)
  1. 1Lactobacillus.
  2. 2Propionibacterium CO₂.
  3. 3Penicillium notatum.
  4. 4Dissolves clots.
  5. 5Monascus.
  6. 6Trichoderma.
  7. 7Aspergillus niger.
  8. 8Controlled fermentation vessel.

Sewage treatment and biogas

From daily life

Cleaning drain water before it reaches the river — the city's biological wash.

Simple definition

Sewage = domestic/industrial waste water. BOD = oxygen needed to break down organic matter in water. Biogas = methane-rich gas from dung/waste.

Sewage, biogasSewage and biogasPrimaryscreeningSecondarybiologicalTertiarydisinfectBiogasfuelPrimary: screening, sedimentation — solids removedSecondary: aeration tank, bacterial flocs, BOD fallsSludge → anaerobic sludge digester → biogasTertiary: disinfection by chlorine/UVBiogas: Methanobacterium; methane 50–70%, CO₂, H₂Gobar gas: dung + water; slurry = manureHigh BOD = more polluted water

In the figure : Sewage treatment and biogas.

Rule 1 : Sewage treatment — Primary: screening, sedimentation — removes solids. Secondary (biological): bacteria form flocs in aeration tanks and digest organic matter ⇒ BOD falls; sludge goes to an anaerobic sludge digester ⇒ biogas. Tertiary: disinfection. Biogas: Methanobacterium and other anaerobic bacteria on dung/waste ⇒ methane 50–70%, CO₂, H₂; fuel and electricity; slurry used as manure. In India ‘gobar gas’ (IARI, KVIC).

  • Easy : Flocs = bacterial clumps.
  • Medium : Low BOD = cleaner.
  • Exam-type (CET) : Methane 50–70%.

Rule 2 : Biogas — Dung, farm waste and kitchen waste decay without air (anaerobic); Methanobacterium ⇒ methane (50–70%), CO₂, H₂, a little H₂S. Uses: cooking gas, lamps, electricity; leftover slurry is good organic manure. Merits: clean fuel, waste disposal, less tree-felling. In India ‘gobar gas’ plants (KVIC, IARI).

  • Easy : Anaerobic = without air.
  • Medium : Slurry = manure.
  • Exam-type (CET) : Methane = fuel.
Remember

P-S-T: solids, biological, disinfection.

Common mistake and CET trap

‘High BOD = clean water’ is wrong. Trap: ‘biogas is mostly CO₂’ is wrong (methane).

Shortcut

Memory clue : "Primary picks solids; secondary bacteria digest".

Spot the difference

StageJob
PrimaryRemove solids
SecondaryBiological digestion
TertiaryDisinfection

Practice questions

Easy
  1. 1What happens in primary?
  2. 2Flocs are?
  3. 3Low BOD means?
Medium
  1. 4Sludge goes to?
  2. 5Main gas in biogas?
  3. 6Biogas bacterium?
Challenging
  1. 7Use of slurry?
  2. 8Tertiary treatment?
Show answers (try them yourself first)
  1. 1Screening, sedimentation.
  2. 2Clumps of bacteria.
  3. 3Cleaner water.
  4. 4Anaerobic digester.
  5. 5Methane.
  6. 6Methanobacterium.
  7. 7Organic manure.
  8. 8Disinfection.

Biocontrol and biofertilisers

From daily life

A ladybird in the garden eats aphids — pest control without spraying.

Simple definition

Biocontrol = using living organisms to control pests/diseases. A biofertiliser = living microbe that improves soil fertility.

Biological solutionsBiocontrol and biofertilisersBiocontrolpest controlBiofertilisersoil fertilityBiocontrol: ladybird (aphids), dragonfly (mosquitoes), Bt (B. thuringiensis)Trichoderma: fungal diseases; baculovirus: insectsMerit: chemical-free, eco-friendly, IPMRhizobium: legume N₂ fixation; Azotobacter, AzospirillumCyanobacteria (Nostoc, Anabaena): rice fields; Azolla + AnabaenaMycorrhiza (Glomus): phosphorus uptake; PSBBiofertiliser = living microbes, not a chemical

In the figure : Biocontrol and biofertilisers.

Rule 1 : Biocontrol — Ladybird (eats aphids), dragonfly (mosquitoes), Bacillus thuringiensis (Bt) — toxin kills caterpillars; Trichoderma — root fungal diseases; baculovirus — specific insects, harmless to others. IPM (Integrated Pest Management): biological + cultural + minimal chemicals. Merits: no pesticide residues, beneficial insects survive, eco-friendly.

  • Easy : Bt = kills caterpillars.
  • Medium : Ladybird = aphid.
  • Exam-type (CET) : IPM = integrated.

Rule 2 : Biofertilisers — Rhizobium: fixes N₂ in legume root nodules; Azotobacter, Azospirillum: free-living bacteria; cyanobacteria (Nostoc, Anabaena) and Azolla + Anabaena: nitrogen in rice fields; mycorrhiza (Glomus): fungus–root symbiosis, absorbs phosphorus and water; PSB: phosphate-solubilising bacteria. Merits: nitrogen/phosphorus available, less chemical fertiliser, improved soil. A biofertiliser is living — not a chemical.

  • Easy : Rhizobium = legumes.
  • Medium : Azolla = rice.
  • Exam-type (CET) : Mycorrhiza = phosphorus.
Remember

R–L: Rhizobium–legume; A–R: Azolla–rice.

Common mistake and CET trap

‘Biofertiliser = urea’ is wrong. Trap: ‘Rhizobium in rice’ is wrong (legumes).

Shortcut

Memory clue : "Bt kills caterpillars, protects crops".

Spot the difference

OrganismUse
RhizobiumN₂ fixation
MycorrhizaPhosphorus uptake
TrichodermaFungal control

Practice questions

Easy
  1. 1Ladybird eats?
  2. 2Bt expands to?
  3. 3Baculovirus acts on?
Medium
  1. 4IPM stands for?
  2. 5Rhizobium lives in?
  3. 6In rice fields?
Challenging
  1. 7Mycorrhiza helps absorb?
  2. 8PSB?
Show answers (try them yourself first)
  1. 1Aphids.
  2. 2Bacillus thuringiensis.
  3. 3Specific insects.
  4. 4Integrated Pest Management.
  5. 5Legume root nodules.
  6. 6Azolla + Anabaena.
  7. 7Phosphorus.
  8. 8Phosphate-solubilising bacteria.

Quick revision of the whole lesson

ConceptKey fact
Plant breedingSelection, crossing, testing; Borlaug
Tissue cultureCallus; auxin–cytokinin; meristem
SCPSpirulina; 50–60% protein
Animal husbandryKurien; Leghorn; AI; MOET
IndustrialPenicillium; Monascus; biogas
BiocontrolBt, ladybird, Trichoderma
BiofertilisersRhizobium, Azolla, mycorrhiza

🎯 Most important points for the exam

  • Plant breeding and the Green Revolution.
  • Mutation, polyploidy, tissue culture.
  • SCP and biofortification.
  • Animal husbandry and allied trades.
  • Industrial microbes, sewage, biogas.
  • Biocontrol and biofertilisers.
  • Summary of varieties and examples.
Study mantra

Understand the concept → draw the figure → memorise the key points → solve questions yourself.