Chapter 9 — Strategies for Enhancement in Food Production — covers plant breeding, animal husbandry, tissue culture, and single cell protein. Carries 3-5 marks. Mostly factual — learn the breeding methods and examples.
Key Concepts
Plant Breeding
Steps: Collection of variability → Evaluation and selection of parents → Cross-hybridisation → Selection and testing → Release of new varieties
Improved Crop Varieties in India
| Crop | Variety | Achievement |
|---|---|---|
| Wheat | Sonalika, Kalyan Sona | Semi-dwarf, high yield (Green Revolution) |
| Rice | IR-8, Jaya, Ratna | Semi-dwarf (from IRRI Philippines) |
| Sugarcane | Saccharum barberi × S. officinarum | High yield + high sugar + thick stems |
| Cowpea | Pusa Komal | Resistant to bacterial blight |
| Brassica | Pusa Swarnim | Resistant to white rust |
Biofortification
Breeding crops with higher nutritional value:
- Vitamin A enriched: Golden rice, carrots, spinach
- Iron enriched: Spinach, bathua
- Protein enriched: Atlas 66 (wheat), protein-rich beans
Tissue Culture
Totipotency: Ability of a single cell to develop into a complete organism
Micropropagation: Growing plants from tissue culture → produces somaclones (genetically identical)
Somatic hybridisation: Fuse protoplasts of two different species → hybrid plant (pomato = potato + tomato)
Micropropagation: Growing plants from tissue culture → produces somaclones (genetically identical)
Somatic hybridisation: Fuse protoplasts of two different species → hybrid plant (pomato = potato + tomato)
Animal Husbandry
- Inbreeding: Mating closely related individuals → increases homozygosity; continued inbreeding → inbreeding depression
- Outbreeding: Mating unrelated animals; includes outcrossing, cross-breeding, interspecific hybridisation
- MOET (Multiple Ovulation Embryo Transfer): Hormones → superovulation → many eggs → IVF → embryos transferred to surrogate mothers
- Artificial Insemination: Semen collected, stored, injected into female
Single Cell Protein (SCP)
- Microorganisms grown as protein-rich food source
- Spirulina: Cyanobacterium grown on wastewater → rich in protein, vitamins, minerals
- 250g Methylophilus methylotrophus → 25 tonnes of protein
Quick Revision Points
- Green Revolution: semi-dwarf wheat (Sonalika) and rice (IR-8)
- Plant breeding steps: collection → selection → crossing → testing → release
- Biofortification: Golden rice (Vit A), Atlas 66 (protein)
- Tissue culture: totipotency, micropropagation (somaclones), somatic hybridisation
- Animal breeding: inbreeding → homozygosity; outbreeding → hybrid vigour
- MOET: superovulation + IVF + embryo transfer
- SCP: Spirulina (protein-rich, grown on waste)
Chapter Navigation
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Related Chapters in Class 12 Biology
- Microbes in Human Welfare Class 12 Notes
- Human Health and Disease Class 12 Notes
- Evolution Class 12 Notes
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