All organisms require food for survival and development. It is essential to increase food production to meet the growing population’s needs. The yield has increased by many folds through plant breeding, animal husbandry and modern technologies such as tissue culture, genetic engineering, and embryo transfer.
Animal Husbandry
It’s the practice of raising and breeding livestock (buffaloes or cattle, sheep, cows, etc.). It includes both poultry farming and fisheries.
Management of poultry and dairy farms is necessary to ensure high-quality breeds with high yielding potential and resistance to disease.
Types and Breeding of Animals
A breed is a group of animals that are closely related in descendance and share common features and appearance.
There are two types: Inbreeding or Outbreeding.
Inbreeding
This refers to the breeding of males and females from the same breed for between 4 and 6 generations. This is done to select superior males and females and then they are mated.
Inbreeding encourages homozygosity and is necessary for the development of pure lines or true breeding species like in Mendel’s case.
Inbreeding is a process that removes unwanted genes and adds superior genes.
Continuous inbreeding causes inbreeding depression which leads to decreased productivity and fertility. It is possible to restore these levels by mating with unrelated superior animals.
Outbreeding
It is the act of mating unrelated animals. It can be one of three types:
- Outcrossing: Matrixing two or more breeds of the same breed. They have not had a common ancestor in a few generations. This can help overcome inbreeding depression.
- Cross-breeding: It allows for the combination of superior traits from two breeds. To achieve this, superior males from one breed are mated to superior females from another breed.
- Hisardale: A result of crossbreeding Marino rams and Bikaneri sheep ewes, a new breed was created in Punjab.
Interspecific Hybridisation: Breeding of two closely related species.
Mule- A hybrid of a male donkey with a female horse.
Controlled breeding experiments can be used to solve many problems associated with normal mating. Control breeding is done using artificial insemination. You can use the sperm immediately or freeze it and transport it later.
Increases hybridisation success with multiple ovulation Embryo Transfer Technology
In this method, the cow is given hormones similar to FSH (Follicle-stimulating hormone) to induce follicular maturation. The result is a higher number of eggs (6-8), than one would get in a normal cycle. The semen from an elite bull is used for mating, or artificial insemination. Fertile eggs are then transferred to surrogate mothers at the 8-32 cell stage.
Bee-keeping (Apiculture)
It’s the care of beehives for honey production. Honey is a beehive-produced nutrient-rich compound. Beeswax can be used in many industries to make cosmetics, polishes and other products. Apis indica is the most popular species of honeybees.
Fisheries
Blue Revolution is a rise in the production of fishes or other aquatic animals.
Aquaculture is the breeding and rearing of aquatic flora (fishes, molluscs and crustaceans), and fauna (aquatic plants and algae) for commercial purposes. Aquaculture can be done in rivers, oceans or lakes. However, intensive aquaculture is done within tanks and ponds.
Pisciculture is a method of raising fish for food and other products. Polyculture is where different species of fish are cultivated together. Monoculture is where different species are grown separately.
Plant Breeding
Plant breeding refers to the manipulation of plants in order to obtain desired traits such as high quality, high yield and resistance against disease.
The Green Revolution refers to an increase in food production to meet the needs of the population. M. S. Swaminathan was the founder of India’s green revolution. For this purpose, modern methods and technologies are employed. Examples – Use of fertilisers, pesticides and high-yielding seeds.
The rise in food grain production has been greatly influenced by high-yield varieties of wheat and rice.
The purpose of plant breeding is to increase yield, quality, tolerance to stress and resistance to various pests and pathogens.
Plant breeding programs are run by various government agencies and companies around the world. These are the steps required to produce a new plant genetic variety.
- Collections of variability- This is the collection all varieties of a crop. It is the collection of all the alleles that correspond to all genes in a plant. This is called germplasm collection.
- Selection of parents and evaluation- The germplasm is evaluated to determine the desired trait.
- Cross Hybridisation- Two characteristics are desired, e.g. Cross-breeding a disease-resistant plant with a plant high in protein is possible.
- Selection and testing superior recombinants- Hybrids with desired characters are chosen and self-pollinated for different generations in order to achieve homozygosity. This ensures that characters don’t segregate in the next generation.
- Commercialization of new cultivars- Quality control is performed to ensure that yield and other quality characteristics, such as disease resistance, are maintained. The crop is grown under controlled conditions in a research field.
For three consecutive seasons, the evaluation is followed by testing in fields of farmers all over the country.
One of the highest yielding hybrid Indian crops
Wheat: Norman E Borlaug created semi-dwarf varieties in Mexico. This increased wheat production from 11 million to 75 millions tonnes.
Kalyan Sona and Sonalika are high-yielding, disease-resistant varieties of wheat that are grown in India.
Rice: Semi dwarf varieties were derived from IR-8, which was developed in the Philippines, and Taichung Native-1 (Taiwan).
Semi-dwarf varieties of rice, Jaya and Ratna, were developed in India.
Sugarcane: Two sugarcane species, Saccharum barberi (cultivated in North India) and the sugar-rich Saccharum oficinarum were successfully cross-bred to produce sugarcane that is high in yield, sugar content, and thick stems.
Millets: High yielding, resistant to water stress varieties of jowar, maize and bajra have been developed in India.
Plant breeding for resistance to disease
Around 20-30% of crops are destroyed by various diseases, including viruses, bacteria and fungi.
Hybridisation and selection are two methods to develop disease-resistant varieties. To obtain a disease-resistant variety, genetic engineering and selection between somaclonal variants can also be used.
Here are some examples of resistant varieties that have been developed using the traditional method of hybridisation.
Mutation Breeding
Mutation results in a change to the gene sequence. To get the desired trait, mutation can be artificially induced.
Examples: A mutation has resulted in a new Moong bean variety that is resistant to yellow mosaic virus and powdery mildew.
High yielding and disease resistance qualities are essential. This combination is achieved by sexual hybridization, where disease-resistant genes can be transferred to high-yielding varieties. A new variety was created of bhindi that is resistant to the yellow mosaic virus and it is called Parbhani Kranti. This wild species was used to transfer the disease resistance quality.
Plant breeding for pest resistance
Large-scale crop destruction is caused by pests and insects. It is very similar to developing disease-resistant varieties.
Here are some examples of pest-resistant varieties that have been developed and are being used commercially:
Improved Food Quality through Plant Breeding
It is important that crops have higher nutrient values to be able to resist disease, pests, and increase yield.
Producing nutrient-rich crops can help improve public health. These crops will be healthier, have higher levels of protein, and contain more vitamins, minerals and are better for the environment.
Biofortification
Biofortification is the process of breeding nutrients-rich crops. Biofortification refers to the process of breeding crops with higher nutritional value such as oil, protein, vitamins, mineral content and micronutrients. Many varieties of vegetables rich with vitamins and minerals have been released by IARI (Indian Agricultural Research Institute), New Delhi.
Here are some examples of biofortified crop varieties:
|
Crop |
Nutrient |
|
Hybrid maize (developed 2000) |
The amino acids tryptophan and lysine are twice as many |
|
Wheat (Atlas 66) |
High Protein content |
|
Rice |
Iron-rich (5 times more) |
|
Carrots, pumpkin, spinach |
Vitamin A enriched |
|
Mustard, tomato, bitter gourd, and bathua |
Vitamin C enriched |
|
Spinach and bathua |
Enriched with iron and calcium |
|
French beans, broad beans, garden peas and lablab beans are all available. |
Protein-enriched |
Single Cell Protein (SCP)
Single-cell protein is one source of protein that can be used to meet the nutritional needs of an ever-increasing animal and human population.
Microbes must be grown on an industrial scale in order to obtain SCP. Blue-green algae such as Spirulina can be grown on wastewater, straw molasses, and animal manure.
Due to its high growth rate, and biomass production, the bacteria Methylophilus can produce 25 tonnes of protein. The growing industry of edible mushrooms can be grown in large quantities.
Tissue Culture
Tissue culture refers to the process of creating a whole plant from a portion of the plant.
Totipotency is the ability of an explant to either regenerate a part of the entire plant or a portion of it.
Micropropagation is a technique using tissue culture that allows you to produce thousands of plants from a single source. The medium must be rich in nutrients. It should contain a carbon source (sucrose), growth regulators(auxins, and cytokinins), vitamins (inorganic salts) and amino acids.
Somaclones
Each of the tissue cultured plants are known as somaclones. They are identical to their parent plants.
Many food crops such as bananas, tomatoes, and apples are available. Tissue culture techniques have been used to produce many food crops on a commercial scale.
Disease infections can be eliminated using the tissue culture method. Remove the virus-free meristems from the plant and grow them in vitro to produce a healthy plant. Banana, potato, and sugarcane meristems have been successfully grown in the laboratory.
Somatic Hybridisation
This is the process of fusing naked protoplasts (protoplast with plasma membrane after digesting cell walls) cells from two different plant varieties that have desirable traits. Somatic hybrids are plants that have been grown using this method.
Pomato was created using tomato and potato, but it did not have the desired combination of traits that could be commercially viable.