Animal Husbandry
Animal husbandry is the branch of agriculture concerned with animals that are raised for meat, fibre, milk, eggs, or other products. It includes day-to-day care, selective breeding and the raising of livestock.
It deals with the care and breeding of livestock like buffaloes, cows, pigs, horses, cattle, sheep, goat, etc. It also includes poultry farming and fisheries. More than 70% of the world’s livestock population is in India and China. Many new technologies have also been applied to achieve improvement in quality and productivity.
The management of farms and farm animals involves the following procedures:
- Dairy farm management: It is the management of animals for milk and its products.
- Poultry farm management: Poultry is the class of domesticated birds used for food or for their eggs which typically includes ducks and chicken.
- Animal breeding: Breeding between animals of the same breed is referred to as inbreeding whereas crossing between different breeds is known as outbreeding. The process of inbreeding causes a rise in the homozygosity hence it is essential to evolve a pure line in any animal. Some other aspects of animal breeding are – outbreeding, out-crossing, cross-breeding, interspecific hybridization. In order to improve the herd, some programmes are also adapted such as – Multiple Ovulation Embryo Transfer Technology (MOET).
- Bee-keeping or apiculture: It is the maintenance of hives of honeybees for the production of honey.
- Fisheries: It deals with catching, processing or selling fish, shellfish or other aquatic animals.
Plant Breeding
Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. It is a technology that has helped increase yields to a large extent.
Green revolution was dependant to a large extent on plant breeding techniques for the development of high-yielding and disease-resistant varieties in rice, wheat, maize etc. Plant breeding is the purposeful manipulation of plant species in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistant.
Steps to breeding a new genetic variety of a crop
- Collection of variability: Genetic variability from various wild relatives of the cultivated species are collected to maintain the genetic diversity of a species. The entire collection of the diverse alleles of a gene in a crop is called the germplasm collection.
- Evaluation and selection of parents: The germplasm is evaluated to identify plants with desirable combination of characters. Selection of parents is picking up seeds of only those plants for multiplication which have the desired traits.
- Cross hybridization among the selected parents: Cross breeding between selected parent is a tedious process because pollen grain from selected male parent is put on the stigma of selected female parent to obtain required trait. But chances of this hybridisation techniques to be successful is very rare.
- Selection and testing of superior recombinants: This is the selection of the plants, from the progeny of hybrids, which have the desired combined character. The selected plants are then self-pollinated for several generation to get a uniformity i.e., homozygosity.
- Testing, release and commercialization of new cultivators: The newly selected lines are evaluated for their yield and other agronomic traits of quality, disease resistance etc. these selected cultivars are then tested with local best cultivar and then are released for commercialisation.
Most common methods of plant breeding
- Hybridization: Hybridization is the process of crossing two genetically different individuals to result in a third individual with a different, often preferred, set of traits. Plants of the same species cross easily and produce fertile progeny.
- Tissue culture: Tissue culture is the growth of tissues or cells in an artificial medium separate from the parent organism. This technique is also called micropropagation. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar.
- Biofortification: Biofortification is the idea of breeding crops to increase their nutritional value. This can be done either through conventional selective breeding, or through genetic engineering.
- Mutation breeding: Mutation breeding, sometimes referred to as "variation breeding", is the process of exposing seeds to chemicals or radiation in order to generate mutants with desirable traits to be bred with other cultivars. Plants created using mutagenesis are sometimes called mutagenic plants or mutagenic seeds.
- Somatic hybridization: Somatic hybridization is a technique which allows the manipulation of cellular genomes by protoplast fusion. Its major contribution to plant breeding is in overcoming common crossing barriers among plant species and in organelle genetics and breeding.
- Plant breeding for improved food quality and developing resistance to insect and pests. Toxins, growth inhibitors and nutritional imbalances are some of the antibiotic factors. Glandular trichomes which produce secondary metabolites contribute to antibiosis in plants. Tolerance refers to plant's ability to grow, reproduce, repair injury and yield satisfactorily under insect-pest attack.
Single Cell Protein (SCP)
Single-cell protein (SCP) refers to protein derived from cells of microorganisms such as yeast, fungi, algae, and bacteria, which are grown on various carbon sources for synthesis.
Spirulina (blue-green algae) can be grown on materials like wastewater from potato processing plants, molasses, straw, sewage to produce large quantities and can serve as food rich in protein, fats, minerals etc. This also helps to reduce environmental pollution.
Certain bacterial species like Methylophilus methylotrophus, because of its high rate of biomass production and growth, can be expected to produce 25 tonnes of protein.
The fact that edible mushrooms are eaten by many people and large scale mushroom culture is a growing industry makes it believable that microscopic fungi too would become acceptable as food.
Tissue Culture
Tissue culture is a method of biological research in which fragments of tissue from an animal or plant are transferred to an artificial environment in which they can continue to survive and function. The cultured tissue may consist of a single cell, a population of cells, or a whole or part of an organ.
This process of generating a whole plant from any cell/plant is called totipotency. The method of producing thousands of plants through tissue culture is called micropropagation and these plants are genetically identical to the original plant from which they are grown.
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