Strategies for Enhancement in Food Production Question Answers: NCERT Class 12 Biology

Animal husbandry deals with the scientific management of livestock. It includes various aspects such as feeding, breeding, and control diseases to raise the population of animal livestock. Animal husbandry usually includes animals such as cattle, pig, sheep, poultry, and fish which are useful for humans in various ways. These animals are managed for the production of commercially important products such as milk, meat, wool, egg, honey, silk, etc. The increase in human population has increased the demand of these products. Hence, it is necessary to improve the management of livestock scientifically.

Micropropagation is a method of producing new plants in a short duration using plant tissue culture.

Some major advantages of micropropagation are as follows:

(a) Micropropagation helps in the propagation of a large number of plants in a short span of time.

(b) The plants produced are identical to the mother plant.

(c) It leads to the production of healthier plantlets, which exhibit better disease-resisting powers.

The major components of medium used for propagation of explants in vitro are carbon sources such as sucrose, inorganic salts, vitamins, amino acids, water, agar-agar, and certain growth hormones such as auxins and gibberellins.

The five hybrid varieties of crop plants which have been developed in India are:

Dairy farm management deals with processes which aim at improving the quality and quantity of milk production. Milk production is primarily dependent on choosing improved cattle breeds, provision of proper feed for cattle, maintaining proper shelter facilities, and regular cleaning of cattle.

Choosing improved cattle breeds is an important factor of cattle management. Hybrid cattle breeds are produced for improved productivity. Therefore, it is essential that hybrid cattle breeds should have a combination of various desirable genes such as high milk production and high resistance to diseases. Cattle should also be given healthy and nutritious food consisting of roughage, fibre concentrates, and high levels of proteins and other nutrients.

Cattle’s should be housed in proper cattle-houses and should be kept in well ventilated roofs to prevent them from harsh weather conditions such as heat, cold, and rain. Regular baths and proper brushing should be ensured to control diseases. Also, time-to-time check ups by a veterinary doctor for symptoms of various diseases should be undertaken.

A breed is a special variety of animals within a species. It is similar in most characters such as general appearance, size, configuration, and features with other members of the same species. Jersey and Brown Swiss are examples of foreign breeds of cattle. These two varieties of cattle have the ability to produce abundant quantities of milk. This milk is very nutritious with high protein content.

Objectives of animal breeding:

(i) To increase the yield of animals.

(ii) To improve the desirable qualities of the animal produce.

(iii) To produce disease-resistant varieties of animals.

Animal breeding is the method of mating closely related individuals. There are several methods employed in animals breeding, which can be classified into the following categories:

(A) Natural methods of breeding include inbreeding and out-breeding. Breeding between animals of the same breed is known as inbreeding, while breeding between animals of different breeds is known as out-breeding. Out-breeding of animals is of three types:

(a). Out-crossing: In this type of out-breeding, the mating of animals occurs within the same breed. Thus, they have no common ancestors up to the last 4-5 generations.

(b). Cross-breeding: In this type of out-breeding, the mating occurs between different breeds of the same species, thereby producing a hybrid.

(c). Interspecific hybridization: In this type of out-breeding, the mating occurs between different species.

(B) Artificial methods of breeding include modern techniques of breeding. It involves controlled breeding experiments, which are of two types:-

(a). Artificial insemination: It is a process of introducing the semen (collected from the male) into the oviduct or the uterus of the female body by the breeder. This method of breeding helps the breeder overcome certain problems faced in abnormal mating.

(b). Multiple ovulation embryo technology (MOET): It is a technique for cattle improvement in which super-ovulation is induced by a hormone injection. Then, fertilization is achieved by artificial insemination and early embryos are collected. Each of these embryos are then transplanted into the surrogate mother for further development of the embryo.

The best method to carry out animal breeding is the artificial method of breeding, which includes artificial insemination and MOET technology. These technologies are scientific in nature. They help overcome problems of normal mating and have a high success rate of crossing between mature males and females. Also, it ensures the production of hybrids with the desired qualities. This method is highly economical as a small amount of semen from the male can be used to inseminate several cattle.

Apiculture is the practice of bee-keeping for the production of various products such as honey, bee’s wax, etc. Honey is a highly nutritious food source and is used as an indigenous system of medicines. It is useful in the treatment of many disorders such as cold, flu, and dysentery. Other commercial products obtained from honey bees include bee’s wax and bee pollen. Bee’s wax is used for making cosmetics, polishes, and is even used in several medicinal preparations. Therefore, to meet the increasing demand of honey, people have started practicing bee-keeping on a large scale. It has become an income generating activity for farmers since it requires a low investment and is labour intensive.

Fishery is an industry which deals with catching, processing, and marketing of fishes and other aquatic animals that have a high economic value. Some commercially important aquatic animals are prawns crabs, oysters, lobsters, and octopus. Fisheries play an important role in the Indian economy. This is because a large part of the Indian population is dependent on fishes as a source of food, which is both cheap and high in animal protein. A Fishery is an employment generating industry especially for people staying in the coastal areas. Both fresh water fishes (such as Catla, Rohu, etc) and marine fishes (such as tuna, mackerel, pomfret, etc.) are of high economic value.

Plant breeding is the process in which two genetically dissimilar varieties are purposely crossed to produce a new hybrid variety. As a result, characteristics from both parents can be obtained in the hybrid plant variety. Thus, it involves the production of a new variety with the desired characteristics such as resistance to diseases, climatic adaptability, and better productivity. The various steps involved in plant breeding are as follows:

(a). Collection of genetic 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.

(b). Evaluation of germplasm and selection of parents: The germplasm collected is then evaluated for the desirable genes. The selected plants with the desired genes are then used as parents in plant breeding experiments and are multiplied by the process of hybridization.

(c). Cross-hybridization between selected parents: The next step in plant breeding is to combine the desirable characters present in two different parents to produce hybrids. It is a tedious job as one has to ensure that the pollen grains collected from the male parent reach the stigma of the female parent.

(d). Selection of superior hybrids: The progenies of the hybrids having the desired characteristics are selected through scientific evaluation. The selected progenies are then self-pollinated for several generations to ensure homozygosity.

(e). Testing, release, and commercialization of new cultivars: The selected progenies are evaluated for characters such as yield, resistance to diseases, performance, etc. by growing them in research fields for at least three growing seasons in different parts of the country. After thorough testing and evaluation, the selected varieties are given to the farmers for growing in fields for a large-scale production.

Biofortification is a process of breeding crops with higher levels of vitamins, minerals, proteins, and fat content. This method is employed to improve public health. Breeding of crops with improved nutritional quality is undertaken to improve the content of proteins, oil, vitamins, minerals, and micro-nutrients in crops. It is also undertaken to upgrade the quality of oil and proteins. An example of this is a wheat variety known as Atlas 66, which has high protein content in comparison to the existing wheat. In addition, there are several other improved varieties of crop plants such as rice, carrots, spinach etc. which have more nutritious value and more nutrients than the existing varieties.

Apical and axillary meristems of plants is used for making virus-free plants. In a diseased plant, only this region is not infected by the virus as compared to the rest of the plant region. Hence, the scientists remove axillary and apical meristems of the diseased plant and grow it in vitro to obtain a disease-free and healthy plant.

Virus-free plants of banana, sugarcane, and potato have been obtained using this method by scientists.

Plant breeding programmes are carried out in a very systematic way, world- wide in government institutions and in many commercial companies. The main steps in breeding a new genetic variety of a crop are as follows:

1. Collection of variability:

Genetic variability is the main element of any breeding programme. In many crops genetic variability which is pre- existing, is available from wild relatives of the crop. Collection and preservation of all the different wild varieties, species and relatives also of the cultivated species followed by their evaluation for their characteristics which is a pre- requisite for effective exploitation of natural genes that is available in the populations.

The entire collection of plants or seeds, having all the diversified alleles for all genes in a given crop is known as germplasm collection.

2. Evaluation and selection of parents:

The germplasm is evaluated to identify the plants with desirable combination of characters. The selected plants are multiplied and then used in the hybridization process. Purelines are created wherever desired and possible.

3. Cross hybridization among the selected parents:

The desired characters have very often to be combined from two different parent plants, for e.g. high protein quality of one parent may need to be combines with the disease resistance from another parent.

This process is possible by cross hybridizing the two parents to produce the hybrids that genetically combine the desired characters in a single plant. This is a very time consuming process since the pollen grains from the desirable plants chosen as male parent, have to be collected and placed on the stigma of the flowers that is selected as female parent.

Also, it is not necessary that the hybrids should combine the required characters, usually only in few hundred to a thousand crosses too shows the desirable combination.

4. Selection and testing of superior recombinants:

This step consists of selecting among the progeny of the hybrids to those plants that contains the desired or required character combinations. The selection process is very crucial or important for the success of the breeding objectives and requires careful scientific evaluation of the progeny. This step yields the plants which are superior for both the parents and they are self -pollinated for several generation till they reach a state of uniformity or equilibrium, so that the characters will not segregate in the progeny.

5. Testing, release and commercialization of new cultivars:

The newly selected lines are evaluated and selected for their yield and other agronomic traits of quality, disease resistance etc. This evaluation is done by the growth of these in the research fields and by recording their performance under ideal or actual fertilizer application, irrigation and other crop management practices.

The evaluation in research fields is followed by testing the materials in farmer’s fields for at least three growing seasons on the several locations in country that represents all the agro-climatic zones when the crop is usually grown. The material is evaluated in comparison to the best available local crop and after this evaluation the variety can be released for the farmers.   

It is easier to culture the plant cells in vitro as compared to animal cells because, the plant cells have the property to grow into the new plant. This property of plant cell is termed as totipotency. This ability is limited in animal cells.

Culture medium is a highly enriched laboratory soil as it provides all the necessary requirements. E.g. carbon source such as sucrose and inorganic salts, vitamins, amino acids and growth regulators like auxins and cytokinins etc. to the growing plant.  

Yes, when a cell dedifferentiates once, it gets regressed back to its embryonic stage and then can again differentiate into any form of tissue. So, the plant tissue culture can be more successful as any kind of tissue can be produced even from differentiated cells.

It is scientifically possible to grow thousand plants from a living cell of any plant and this this process is called micropropagation. The property of the plant cells that helped them to grow into a new plant is totipotency.

Micropropagation is the use of plant cell culture to regenerate large number of plants. This results in genetically identical plants and is also called clonal propagation. Hence, the desirable characters are kept constant for many generation. Micropropagation is widely used in forestry and in floriculture. Plants can be obtained throughout the year under controlled conditions.   

A breed is a specific group of animals or plants having homogenous appearance, behaviour and other characteristics that can distinguish it from other animals or plants of the same species. E.g. Afghan shepherd, American bulldog etc.

Species is one of the basic units of biological classification and a taxonomic rank. It can be defined as the largest group of organisms capable of interbreeding and producing fertile offspring. E.g. lion, cow, dog are species.  

Plants raised through tissue culture are very useful because they are identical copy of the parent tree. This is of great use when desirable traits of the parent plant have to be maintained.

Before the new plants are generated through plant breeding programs, they need to be evaluated for their yield and other agronomic traits of quality, disease resistance etc.

The testing is done on the farmer’s field for at least three growing seasons at different locations in the country representing all the agro-climatic zones, where the crop is usually grown. The material is evaluated in comparison to the best available local crop cultivar known as a check for reference cultivar.  

Stress for plants can be defined as any external factor that negatively influences plant growth, productivity, reproductive capacity or survival. This includes a wide range of factors which can be broadly divided into abiotic or environmental stress factors like salinity, extreme temperatures, drought etc. and biotic or biological stress factors.

Natural selection is a gradual, non- random process by which biological traits become wither more or less common in a population as a function of differential reproduction of their bearers. In natural selection the environment acts as a sieve through which only certain variations can pass.

Artificial selection is a process in which animals and plants desirable traits are considered by human breeders and favoured for reproduction. It is an artificial mechanism by which evolution can occur. It is also called selective breeding as it promotes traits that suit human preferences. In contrast to natural selection, here the evolution is intentional or guided.  

When breeding is between animals of the same breed, it is called inbreeding, if we want to evolve a pureline in any animal, inbreeding is necessary. It also helps in the accumulation of the superior genes and elimination of less desirable genes by increasing homozygosity.  

1. The shift from grain to meat diets creates more demand for cereals because it takes 3- 10 kg of grain to produce 1 kg of meat by the animal farming.
2. This research is related to the single cell protein.

Microbes are being grown on an industrial scale as the source of good protein. Microbes like Spirulina can be grown easily on materials such as wastewater from potato processing plants, straw, molasses, animal manure and even sewage too, for the production of large quantities and can serve as food which is rich in protein, minerals, fats, carbohydrates and vitamins. Such utilization also produces the environmental pollution effects.  

Cell wall is the most important physical barrier in protoplast fusion experiments. This can be overcome by treatment with enzymes like cellulase and pectinase which have the ability to digest the cell wall and liberate the naked protoplast surrounded only by the cell membrane.  

Maize, wheat, rice, bathua, spinach, pulses all these crops contains biofortified varieties. Maize hybrids contains twice the amount of amino acids, fortified wheat variety which has high content of proteins and fortified rice has high quantity of iron.

Consumption of these types of biofortified foods will enrich the nutritive value of our common foods and will majorly improve public health.

Instead of consuming different food items for obtaining the different nutrients, if 2 or 3 nutrients can be incorporated into a single crop then it would leads to enormous benefits to the human beings and may even help to overcome several nutrient deficiency disorders latent in our country.

Contribution of Dr. MS Swami Nathan are as follows:

1. Introduction of short, high yielding varieties of wheat in India.
2. Development of short duration, high yielding varieties of rice.  

The desirable trait can be different for different plants. The breeders have tried to incorporate these into the crop plants. The list may be as follows:

1. Increased tolerance to environmental stress like salinity, extreme temperature etc. e.g. Hybrid maize, jawar and bajra which are resistant to water stress.
2. Resistance to pathogens e.g. moong bean
3. Increased tolerance to insect pests e.g. a new variety of Brassica is resistant to aphids.
4. High yielding and improved quality of crop plants e.g. Atlas 66 used as a donor for the developing wheat varieties with improved protein content.  

As traditional breeding methods failed to keep pace with demands and to sufficiently provide fast and efficient systems for the improvement in crop plants, another technology is known as tissue culture, has been developed. The advantages of tissue culture over conventional breeding are as follows:

1. It can be used to produce large number of plantlets within a short period by micropropagation.
2. All cells in the culture are derived from a single explant by mitotic division, therefore all have the similar genotype and constitute a clone.
3. Tolerance to stress can be obtained by providing pollutants, toxins, salts etc. in culture medium in increasing dosage. The surviving healthy cells are selected for raising resistant plants.
4. Virus free plantlets can be obtained by meristem culture.
5. Embryos which do not survive inside seeds can be grown by tissue culture to form new plants.

With the increasing population of the world, enhancement of food production is a major necessity. Modern biological principles that has been applied to animal husbandry and plant breeding have a major role in our efforts to increase the production of food. These modern techniques include both the embryo transfer technology and tissue culture techniques.

MOET or Multiple Ovulation Embryo Transfer is a programme that has been successfully used for cattle, sheep, buffalo etc. that benefits in high milk yielding breeds of female are breed with high quality meat yielding bulls to increase herd size and it ensures good quality of progeny. It is also economic and time saving process to obtain the desirable progeny.

The procedure for MOET is as follows:

1. A cow is administered hormones with FSH- like activity to induce follicular maturation and super ovulation.
2. The cow produces 6-8 eggs instead of one egg produced normally.
3. It is now, either mated with an elite bull or artificial insemination is carried out.
4. When the fertilized eggs attain 8- 32 celled stage, they are non- surgically removed and transferred to a surrogate mother.
5. The genetic mother can now be again super ovulated.

Modern methods in plant breeding involves following:

1. Tissue culture is an in vitro technique of regeneration of a whole plant from any part of a plant (explant) by growing it on culture medium under aseptic conditions.
2. Biofortification is the method for developing crops with higher levels of vitamins, minerals, proteins and healthier fats to improve public health.
3. Single cell protein is an alternative protein source for animal and human nutrition from certain beneficial microorganisms like Spirulina.   

Yes apiculture offers many advantages to farmers such as:

1. Honey produced by honeybees, is a food of high nutritive value.
2. It is used in the indigenous system of medicine.
3. Honeybee also produces beewax, which is used in the preparation of cosmetic and polishes of various kinds.

If apiculture is done near a place of commercial flower cultivation it offers several advantages. Bees are the pollinators of many crop species such as sunflower, Brassica, apple and pear. Keeping beehives in crop fields during flowering period.

1. Increases pollination efficiency.
2. Improved the yield which is beneficial both from the point of view of crop yield and honey yield.

1. It is possible to induce mutations artificially in plants through the use of chemical or radiations and then selecting and using those plants that have the desirable character as a source in breeding. This process is called mutation breeding. In mung bean, resistance to yellow mosaic virus and powdery mildew was induced by mutations.
2. Traditional farming can only yield a limited biomass which is used as food for humans and animals. Better management practices and increase in agricultural land area can increase yield of biomass but only to the limited extent. Plant breeding as a technology has helped in increasing the production to a very large extent.

Plant breeding is the purposeful manipulation of plant species in order to create desired plant typed which are better suited for cultivation and gives better yields; and are diseases resistant plant. This technology has given support to green revolution which was responsible for not merely meeting the national requirements in food production but it also helped us in the exportation.  

Plant cell totipotency can be utilized for plant propagation and improvement

1. By application of these methods it is possible to achieve propagation of a large number of plants in very short time. Plants like tomato, banana, apple etc., have been produced on commercial scale.
2. Healthy plants can be recovered from diseased plants by micropropagation. This is done by removing the meristem, which is disease free and growing it in vitro. This has been done in banana, sugarcane, potato etc.  

Traditional farming can only yield a limited biomass as food for humans and animals. Better management practices and increase agricultural land can increase yield, but only to a limited extent.

Following are the three options to increase food production:

a. Single cell protein The biomass obtained from microorganisms can be treated or processed in industry to be used as food and is called single cell protein.

Merits of single cell protein:

1. Its production reduces pollution as it uses organic waste and industrial effluents.
2. It provides a protein rich diet.
3. It fulfills the demand of protein for human diet and takes off the pressure in agricultural system.

Demerits of single cell protein:

1. Sometimes as the microbial biomass when taken as diet supplement may lead to allergic reactions.
2. Manu types of microorganisms produce substances which are toxic to the humans and also to the animals.   

b. Biofortification It is the method for developing crops with higher levels of vitamins, minerals proteins and healthier fats to improve public health.

Merits of Biofortification:

1. It can increase yields grown in the same or less acreage.
2. It can potentially improve nutritional value or other health benefits.

Demerits of Biofortification:  

1. Its successful implementation into society required safe delivery systems, stable policies appropriate social infrastructures.
2. It continued by financial support also.

c. Tissue culture It is an technique for regeneration of a whole plant from any part of a plant by growing it on culture medium under aseptic conditions.

Merits of tissue culture:

1. A large number of plants can be grown in short time.
2. Disease free plants can be multiplied.
3. Seedless plants can be multiplied.
4. The plants where sexual reproduction is absent may undergo somatic hybridization.

Demerits of tissue culture:  

1. It requires great expanses because it needs latest techniques in the laboratory.
2. It requires acclimatization of plants grown by tissue culture to the external environment.
3. It requires special expertise.

Features of plants that will prevent insect and pest infestation are:

1. Increasing hair growth on aerial parts of the plants.
2. Rendering the flowers nectarless.
3. Enabling plants to secrete insect killing chemicals (toxins).