Strategies for Enhancement in Food Production Class 12 Notes

Animal Husbandry: Breeding and Management

Animal husbandry is the agricultural practice of breeding and raising livestock like buffaloes, cows, pigs, horses, cattle, sheep, camels, and goats. It encompasses practices like dairy farm management, poultry farm management, and fisheries, which are vital for providing milk, eggs, meat, and other products. A key aspect is animal breeding, which aims to increase the yield and improve the desirable qualities of the product.

Breeding is of two main types:

1. Inbreeding: Mating of more closely related individuals within the same breed for 4-6 generations. It increases homozygosity and helps in evolving a pure line. However, continued inbreeding can lead to inbreeding depression, which is the reduction in fertility and productivity. This is overcome by a single out-cross.
2. Out-breeding: Breeding of unrelated animals. This includes:

• Out-crossing: Mating animals of the same breed but having no common ancestors on either side of their pedigree up to 4-6 generations. It is the best method to overcome inbreeding depression.
• Cross-breeding: Superior males of one breed are mated with superior females of another breed. The progeny (hybrid) often have desirable qualities from both parents. For example, Hisardale sheep were developed by crossing Bikaneri ewes and Marino rams.
• Interspecific Hybridisation: Mating animals from two different but related species. The progeny combine desirable features of both parents but are often sterile. Example: Mule (cross between male donkey and female horse).

Modern controlled breeding includes Artificial Insemination (AI), where semen from a superior male is collected and injected into the reproductive tract of a selected female, and Multiple Ovulation Embryo Transfer (MOET), a technique to improve herd genetics by producing multiple eggs, fertilizing them, and transferring them to surrogate mothers.

Steps in Plant Breeding

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Key Terms and Definitions

Animal Husbandry

The agricultural practice of caring for and breeding domestic animals, such as cattle, hogs, sheep, and horses.

Inbreeding Depression

The reduced biological fitness in a given population as a result of inbreeding, i.e., breeding of related individuals.

MOET

Multiple Ovulation Embryo Transfer. A technique where a cow is administered hormones (like FSH) to induce superovulation, artificially inseminated, and the embryos are recovered non-surgically and transferred to surrogate mothers.

Biofortification

The process of breeding crops to increase their nutritional value, such as higher levels of vitamins, minerals, or protein.

Totipotency

The inherent potential of a plant cell to grow and develop into a whole plant, given suitable culture conditions.

Somatic Hybridisation

The process of producing a hybrid plant by fusing isolated somatic protoplasts (cells without a cell wall) from two different plant species and then growing the hybrid cell into a plant.

Single-Cell Protein (SCP)

Edible protein produced by pure or mixed cultures of microorganisms like algae, fungi, yeast, or bacteria, grown in large quantities for use as a protein supplement.

Germplasm Collection

The collection of all the diverse alleles for all genes in a given crop, preserved in the form of seeds or plants, serving as a resource for breeding programs.

Apiculture

The science and art of rearing, and managing honey bees; beekeeping.

Inbreeding vs. Outbreeding

Must-Remember Concepts

• MOET (Multiple Ovulation Embryo Transfer) uses hormones like FSH to induce superovulation (6-8 eggs) and increases herd size rapidly via surrogate mothers.
• Hisardale sheep, a result of cross-breeding Bikaneri ewes and Marino rams, is a prime example of creating a new breed with combined desirable traits.
• Interspecific hybridization creates animals like mules (male donkey + female horse), but the offspring are typically sterile.
• The Green Revolution in India was powered by semi-dwarf wheat (Sonalika, Kalyan Sona) and rice (Jaya, Ratna) varieties.
• Biofortification is about nutritional enhancement, not just yield. Examples include Vitamin A-enriched rice and iron-fortified wheat.
• Saccharum barberi (North India, low sugar) and Saccharum officinarum (South India, high sugar) were crossed to produce a high-yield, high-sugar cane variety suitable for North India.
• Single-Cell Protein (SCP) from microorganisms like Spirulina can be grown on waste materials, converting waste into a protein-rich food source and reducing pollution.
• Somatic hybridization requires digesting the cell wall with enzymes (cellulase, pectinase) to fuse protoplasts and create a somatic hybrid, like the 'pomato'.
• The principle of plant tissue culture is totipotency, and it requires a sterile nutrient medium with growth regulators like auxins and cytokinins.
• Virus-free plants can be obtained by meristem culture (apical and axillary) because the meristem is generally free of viruses.

Applications of Breeding Strategies

• {"item":"Disease Resistance in Crops","description":"The mung bean variety resistant to yellow mosaic virus and powdery mildew was developed through mutation breeding."}
• {"item":"Insect Resistance in Crops","description":"Pusa Gaurav, a variety of brassica (rapeseed mustard), was developed to be resistant to aphids."}
• {"item":"Biofortified Crops","description":"Atlas 66, a wheat variety with high protein content, has been used as a donor for improving cultivated wheat."}

Exam Tip: Common Mistakes & Scoring Points

Students often confuse out-crossing and cross-breeding. Remember, out-crossing is within the same breed but with no common ancestors, while cross-breeding is between different breeds. Be precise. When explaining MOET, always mention the use of FSH-like hormones to induce super-ovulation and the use of surrogate mothers. For tissue culture, highlight totipotency as the principle and the need for a sterile (aseptic) nutrient medium with plant growth regulators (auxins & cytokinins). These keywords fetch full marks.

Practice Questions with Solutions

• What is the main objective of MOET technology? To increase the success rate of producing desirable hybrids and to rapidly increase the herd size by using surrogate mothers for embryo development.
• Define biofortification and give one example. Biofortification is the breeding of crops with higher levels of essential nutrients like vitamins, minerals, or proteins. Example: Golden rice, which is enriched with Vitamin A.
• What is the scientific principle behind producing thousands of plants through tissue culture? The scientific principle is totipotency, which is the capacity of a single plant cell (explant) to regenerate into a whole plant under sterile lab conditions on a nutrient medium.
• Name the parents of the hybrid sugarcane variety grown in North India. The parents were Saccharum barberi (originally grown in North India) and Saccharum officinarum (tropical canes from South India).

Frequently Asked Questions

Frequently Asked Questions