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

Millions of chicken were killed or rejected in West Bengal, Assam, Odisha and Maharashtra because they were found to be infected with H₅N₁, which is the casual organism of bird flu.

The ability of a protoplast that is obtained from two different cells, to fuse and form a hybrid protoplast is known as protoplast fusion.  

Meristem have the ability to divide continuously throughout their life. Their walls are thin and elastic to facilitate the division so they are suitable for tissue culture. Permanent cells loses their ability to divide and their walls are thick. They need to differentiate to divide so they are not easy to culture.  

Single cell proteins are the proteins that are obtained from unicellular organisms or microorganisms. Spirulina is one of the unicellular microbe. Thus, the proteins synthesized by Spirulina are known as single cell proteins.

The person with allergies to pulses is advised to take Spirulina daily due to the following reasons that are as follows:

1. It could be a substitute for protein rich pulses.
2. Spirulina is rich in beta- carotene and anti- oxidants besides all these essential amino acids which helps in improving the allergic symptoms appeared due to consumption of pulses.

When culturing of aquatic plants and animals, it is done in freshwater bodies which is known as aquaculture. Examples of animals that can be multiplied by aquaculture are as described below:

Finfish: Tilapia, Carp, Catfish etc.

Shellfish: Shrimps, Oysters etc.   

A veterinary doctor has to ensure proper and safe farm conditions to keep the animals free from diseases and treat them appropriately if they are diseased.

No, there is nothing wrong to call the plants which are obtained through micro- propagation as clones because each of these plants will be genetically identical to each other and the parent plant or we can say heritable.

Somatic hybrids are obtained by protoplasts formation from two different varieties of plants and then further cultured to form a new plant. Compatibility between two plants is not a limitation. Any two protoplasts can be formed together. Whereas, hybrids are obtained by crossing two selected parent plants of opposite or different sex. Many times compatibility is a limitation for the breeding.  

Removal of stamens from the bisexual flower which is used as a female parent in plant hybridization process is known as emasculation. This is done to avoid the unwanted self- pollination which has been done at bud condition before the anthers dehisce (cut or wounded).  

The limitations of plant hybridization programme includes various points:

1. Availability of a limited number of identified diseases resistant genes that are present in various crop varieties or wild relatives.
2. Compatibility of parents.
3. Time consuming and tedious process.  

No radiation treatment has been used to create thousands of new plant varieties. These type of varieties are cultivated as food and feed. Radiation is commonly known to be much more disruptive for the chromosomal structure than the manipulations that is used to make transgenic plants.

Such type of radiation treatment of crop plants has caused no documented instances of ill- health among the consumers instead of having been used commercially for several decades. For rice crops only, hundreds or thousands of different mutant varieties have been developed mostly made by using ionizing radiations such as gamma rays.  

In interspecific crosses, male and female animals of two different related species are being mated. In some cases, the progeny may combine desirable features of both the parents and can be of considerable or desirable economic value. E.g., the mule.

An interspecific hybrid’s fertility varies from different points. Many of Panthera species varieties like tigers, lions, leopard hybrid males are infertile, while the female counterparts can breed with the species that she contains (female tigers can breed with a lion or tiger to produce ligers or tigers). These are rare in nature.

Intergeneric hybridization is the crossing of two different animals or plants of different genus. It is almost unknown in nature. Intergeneric hybrids more or less never form a complete zygotes or an embryos. These are sterile or we can say infertile.   

Fish farming in isolated water bodies is known as pisciculture.

Similarly, when culturing of aquatic plants and animals which is done in freshwater bodies, is known as aquaculture.  

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.  

The loss in fertility and vigor occurs after the inbreeding because the recessive alleles tends to get together and express very harmful effects in the offspring.  

Collection and preservation of all the different wild varieties, species and relatives of the cultivated species is important for effective exploitation of natural genes available in the population. E.g. sources of resistance genes may be cultivated varieties, germplasm collection of the crop or wild relatives.  

Triticale is a man- made cereal. It was developed by crossing Triticum aestivum (common wheat) and Secale cereal (European rye). Triticale seed grain is being used as a wheat substituted in some parts of the world.   

1. Mating of closely related individuals within the same breed is known as inbreeding.
2. Mating of animals of same breed but contains no common ancestors or either side for 4-6 generations is known as outbreeding.
3. Mating of animals of two different or unrelated species is called interspecific hybridization.
4. Breeding of animals that belongs to different breeds is called cross- breeding.   

Consumption of food which is deficient in nutrients particularly, micronutrients, proteins and vitamins is known as ‘hidden hunger’.  Plants obtained by protoplast culture are known as somatic hybrids as they are formed by the fusion of isolated protoplasts from two different varieties of plants in which each is having a desirable character to obtain a hybrid protoplast which can be further grown to form a new plant.

Plants obtained by protoplast culture are known as somatic hybrids as they are formed by the fusion of isolated protoplasts from two different varieties of plants in which each is having a desirable character to obtain a hybrid protoplast which can be further grown to form a new plant.The ability of a protoplast that is obtained from two different cells, to fuse and form a hybrid protoplast is known as protoplast fusion.  

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.