Learning Objectives
- Understand plant and animal breeding techniques
- Learn about single cell protein and tissue culture
- Study bee-keeping, fisheries, poultry, and dairy farming
Key Concepts
Plant Breeding
Purposeful manipulation of plant species to create improved varieties. Steps: (1) Collection of variability (germplasm collection), (2) Evaluation and selection of parents, (3) Cross hybridization, (4) Selection and testing of superior recombinants, (5) Testing, release, and commercialization.
Green Revolution: Norman Borlaug (Father of Green Revolution worldwide), M.S. Swaminathan (India). Semi-dwarf wheat varieties (Sonalika, Kalyan Sona) and rice varieties (IR-8, Jaya, Ratna) increased food production. Biofortification: Breeding crops with higher nutritional value. Examples: Vitamin A-enriched carrots, iron-fortified fortified rice, protein-enriched beans and legumes. Atlas 66 wheat — high protein content.
Disease resistance breeding: Himgiri wheat (resistant to leaf/stripe rust, hill bunt), Pusa Swarnim mustard (white rust resistant), Pusa Sadabahar chilli (resistant to chilli mosaic virus).
Mutation breeding: Inducing mutations using chemicals or radiation to create desired traits. Mung bean variety resistant to yellow mosaic virus and powdery mildew developed by mutation breeding.
Animal Breeding
Inbreeding: Mating closely related animals (4-6 generations). Increases homozygosity. Used to develop pure lines. Drawback: inbreeding depression (reduced fertility and productivity). Overcome by outcrossing. Outbreeding: Mating unrelated animals. Types: (1) Out-crossing (within same breed, no common ancestor for 4-6 generations), (2) Cross-breeding (between different breeds — e.g., Hisardale sheep = Bikaneri ewes x Merino rams), (3) Interspecific hybridization (different species — mule = male donkey x female horse).
MOET (Multiple Ovulation Embryo Transfer): Cow given FSH-like hormones → superovulation (6-8 eggs instead of 1) → artificial insemination → embryos collected at 8-32 cell stage → transferred to surrogate mothers. Increases herd improvement rate.
Other Important Topics
Apiculture (Bee-keeping): Apis mellifera (Italian bee) preferred. Products: honey, beeswax. Fisheries: Aquaculture (fish farming) and mariculture (marine organisms). Blue Revolution = rapid expansion of fisheries. Single Cell Protein (SCP): Microbial biomass grown on industrial waste as protein-rich food. Spirulina (cyanobacterium), Methylophilus methylotrophus grown on methanol. Can reduce environmental pollution.
Tissue Culture / Micropropagation: Growing plants from small tissue pieces (explants) on nutrient medium. Produces somaclones (genetically identical plants). Meristem culture produces virus-free plants. Somatic hybridization: Fusion of protoplasts from different species → hybrid protoplast → somatic hybrid (pomato = potato + tomato).
Summary
Plant breeding involves hybridization, selection, and mutation breeding to improve crop varieties. Animal breeding uses inbreeding, outbreeding, and MOET for improvement. Biofortification creates nutritionally enriched crops. Single cell protein and tissue culture offer alternative food production strategies.
Important Terms
- Germplasm: Total collection of genes and alleles in a crop species
- Biofortification: Breeding crops with enhanced nutritional quality
- Inbreeding depression: Decline in fitness due to increased homozygosity
- MOET: Multiple Ovulation Embryo Transfer for rapid herd improvement
- Somaclones: Genetically identical plants produced by tissue culture
- Somatic hybridization: Fusion of protoplasts from different species
- SCP: Single Cell Protein — microbial biomass used as food
- Micropropagation: Rapid multiplication of plants through tissue culture
Quick Revision
- Plant breeding steps: Germplasm → Selection → Hybridization → Testing → Release
- Green Revolution: Borlaug (world), Swaminathan (India)
- Biofortification: Atlas 66 (high protein wheat), vitamin A carrots
- Inbreeding depression: overcome by outcrossing
- Hisardale sheep = Bikaneri x Merino (cross-breeding)
- MOET: superovulation → embryo transfer to surrogates
- Spirulina: SCP source (cyanobacterium)
- Tissue culture: explant → callus → plantlets (somaclones)