NCERT Solutions Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production

Question. Explain in brief the role of animal husbandry in human welfare.
Answer. Animal husbandry is the practice of taking care and breeding domestic animals by applying scientific principles. It includes feeding, breeding and raising animal livestock whose primary purpose is to provide meat and milk. Milk is considered as an important article of regular diet. The animal protein is obtained from beef, cattle, sheep and meat of goats. Eggs and poultry meat also serve as sources of animal protein. Thus, animal husbandry plays an important role in human welfare by providing us milk, eggs, meat, wool, silk, honey, wax and many other products. Also, rearing of animals provide useful employment to many.

Question. If your family owned a dairy farm, what measures would you undertake to improve the quality and quantity of milk production?
Answer. The following efforts need to be put in:
(i) The cattle in the dairy farm must be housed and fed properly.
(ii) Cleanliness should be maintained in the milking area.
(iii) The health of the dairy cattle should be of utmost importance and a veterinary doctor must visit regularly.
(iv) Regular inspections of the farm, maintaining records, identification and rectification of problems should be done along with maintaining precautionary measures.
(v) Milking should be done in a dirt-free area and all the sanitary conditions should be maintained.
(vi) High-yielding and disease-resistant breeds can be selected to maximise benefits.

Question. What is meant by the term ‘breed’? What are the objectives of animal breeding?
Answer. Breed refers to the group of animals having same ancestral characters, general appearance, size, etc.
Objectives of animal breeding:
(i) To increase the quantity of yield.
(ii) To improve the desirable qualities of the produce.

Question. Name the methods employed in animal breeding. According to you which of the methods is best? Why?
Answer. The methods employed in animal breeding are:
(i) Natural methods: These can be carried out by inbreeding and outbreeding methods.
(ii) Artificial methods: These are carried out by artificial insemination and multiple ovulation embryo transfer (MOET).
The artificial method of animal breeding is best as it ensures good quality of progeny. It is also economic and time saving process to obtain the desirable progeny.

Question. What is apiculture? How is it important in our lives?
Answer. Apiculture is the rearing, caring and management of honeybees for obtaining honey and wax.
Importance:
(i) It produces beeswax, used in the industry for making cosmetics, polishes, etc.
(ii) Honey has high nutritive value.
(iii) Bees act as pollinators of many crop species like sunflower, Brassica, etc, and thus increases crop yield.

Question. Discuss the role of fishery in enhancement of food production.
Answer. Fishery is an industry related to the catching, processing and selling of fish, shellfish or other aquatic animals. Fishes are rich in proteins, vitamins and minerals, and are considered as complete food. Fish liver oil is used in medicine industry. A large part of human population depends on fish and fish products and other aquatic animals such as prawn, crab, lobster, edible oyster, etc., for food. Fishery provides income and employment to a large number of fishermen in coastal states.

Question. Briefly describe various steps involved in plant breeding.
Answer.
- Earlier methods of plant breeding involved crossing or hybridising pure lines, followed by artificial insemination to produce plants of desirable traits.
- The major steps in breeding a new genetic variety of a crop are as follows:

(i) Collection of variability
- Genetic variability is the root of any breeding programme.
- Pre-existing genetic variability is collected from wild varieties, species and relatives of the cultivated crop species.
- These are evaluated for their characteristics and preserved for effective exploitation of the natural genes.
- The entire collection of diverse alleles for all genes in a given crop is called germplasm collection.

(ii) Evaluation and selection of parents
- Evaluation of germplasm is carried out to identify plants with desirable combination of characters.
- The selected plants are multiplied and hybridised.
- By self-pollination, pure line is created whenever desired.

(iii) Cross-hybridisation among the selected parents
- The cross-hybridisation between the parents is done to produce hybrids that genetically combine to give desired characters in one plant.
- Cross-hybridisation is a time-consuming and tedious process because it involves emasculation and bagging techniques to transfer desired pollen grains to the desired plant.
- The chances of the desirable characters combining in the hybrid is also one in few thousand crosses.

(iv) Selection and testing of superior recombinants
- It involves the selection of plants among the progeny of the hybrids with desired combination of characters.
- The hybrid are superior to both the parents. This is called hybrid vigour/heterosis.
- They are self-pollinated for several generations till they reach a state of uniformity or homozygosity in order to avoid the segregation of characters in the future progeny.

(v) Testing, release and commercialisation of new cultivars
(a) Evaluation
- The newly selected lines are evaluated for their yield and other agronomic traits of quality, disease resistance, etc., by growing them in the research fields.
- Their performance is recorded under ideal fertiliser application, irrigation and other crop management practices.
(b) Testing
- After evaluation, the hybrid line is tested in farmer’s fields
- The crop is grown at different locations in the country with different agroclimatic zones for at least three growing seasons.
- The tested material is evaluated in comparison to the best available local crop cultivar (called check or reference cultivar) as a reference material for marketing of the material.
(c) Release
OU The material tested is then selected to be certified and released in bulk as a variety.

Question. Explain what is meant by biofortification.
Answer. Biofortification is a crop breeding programme that is aimed for developing crop with high levels of vitamins, minerals, proteins and fats to improve public health.

Question. Which part of the plant is best suited for making virus-free plants and why?
Answer. The terminal bud having apical meristem are the best suited parts of plant for making virus-free plant because they are not infected by virus.

Question. What are the major advantages of producing plants by micropropagation?
Answer. Major advantages of producing plants by micropropagation are:
(i) Large number of plants can be grown in short time.
(ii) Disease-free plants can be obtained.
(iii) Plants that have lost the capacity to produce seeds can be grown.
(iv) The plants where sexual reproduction is absent, may be hybridised by tissue culture.
(v) Plants produced are genetically similar to the parent and have all its characteristics.

Question. Find out what the various components of the medium used for propagation of an explant in vitro are.
Answer. The major components of the medium for in vitro propagation are:
(i) Water
(ii) Agar agar
(iii) Sucrose
(iv) Inorganic salts
(v) Vitamins
(vi) Amino acids
(vii) Growth hormones like auxin, cytokinins.

Question. Name any five hybrid varieties of crop plants which have been developed in India.
Answer. (i) Cauliflower varieties — Pusa Shubhra and Pusa Snowball K-1
(ii) Brassica varieties — Pusa Swarnim (Karan rai)
(iii) Wheat varieties — Himgiri
(iv) Rice varieties — Jaya and Ratna
(v) Chilli varieties — Pusa Sadabahar.

NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production Multiple Choice Questions

Question. Which one of the following is a marine fish? 
(a) Rohu
(b) Hilsa
(c) Catla
(d) Common Carp
Answer. B

Question. ‘Himgiri’ developed by hybridization and selection for disease resistance against rust pathogens in a variety of
(a) chilli
(b) maize
(c) sugarcane
(d) wheat
Answer. D

Question. Which one of the following products of apiculture is used in cosmetics and polishes
(a) Honey
(b) Propolis
(c) Wax
(d) Royal jelly
Answer. C

Question. In plant breeding programmes, the entire collection (of plants seeds) having all the diverse alleles for all genes in a given crop is called
(a) evaluation and selection of parents
(b) germplasm collection
(c) selection of superior recombinants
(d) cross-hybridisation among the selected parents.
Answer. B

Question. A collection of all the alleles of all the genes of a crop plant is called 
(a) germplasm collection
(b) protoplasm collection
(c) herbarium
(d) somaclonal collection
Answer. A

Question. A protoplast is a cell
(a) undergoing division
(b) without cell wall
(c) without plasma membrane
(d) without nucleus.
Answer. B

Question. In virus-infected plants the meristematic tissues in both apical and axillary buds are free of virus because 
(a) the dividing cells are virus resistant
(b) meristems have anti viral compounds
(c) the cell division of meristems are faster than the rate of viral multiplication
(d) Viruses cannot multiply within meristem cell(s).
Answer. C

Question. Which one of the following combination would a sugarcane farmer look for in the sugarcane crop?
(a) Thick stem, long internodes, high sugar content and disease resistant
(b) Thick stem, high sugar content and profuse flowering
(c) Thick stem, short internodes, high sugar content, disease resistant
(d) Thick stem, low sugar, content, disease resistant
Answer. A

Question. Breeding of crops with high levels of minerals, vitamins and proteins is called
(a) somatic hybridization
(b) biofortification
(c) biomagnification
(d) micropropagation
Answer. B

Question. Superovulation is induced by
(a) artificial insemination
(b) more mating
(c) hormonal injection
(d) Any of these
Answer. C

Question. The scientific process by which crop plants are enriched with certain desirable nutrients is called 
(a) crop protection
(b) breeding
(c) biofortification
(d) bioremediation.
Answer. C 

Question. Micro-propagation is 
(a) propagation of microbes in vitro
(b) propagation of plants in vitro
(c) propagation of cells in vitro
(d) growing plants on smaller scale.
Answer. B

Question. Given below are a few statements regarding somatic hybridisation.
Choose the correct statements.
(i) Protoplasts of different cells of the same plant are fused
(ii) Protoplasts from cells of different species can be fused
(iii) Treatment of cells with cellulase and pectinase is mandatory
(iv) The hybrid protoplast contains characters of only one parental protoplast.
(a) (i) and (iii)
(b) (i) and (ii)
(c) (i) and (iv)
(d) (ii) and (iii)
Answer. D

Question. An explant is 
(a) dead plant
(b) part of the plant
(c) part of the plant used in tissue culture
(d) part of the plant that expresses a specific gene.
Answer. C

Question. The biggest constraint of plant breeding is 
(a) availability of desirable gene in the crop and its wild relatives
(b) infrastructure
(c) trained manpower
(d) transfer of genes from unrelated sources.
Answer. A

Question. Several South Indian states raise 2-3 crops of rice annually. The agronomic feature that makes this possible is because of 
(a) shorter rice plant
(b) better irrigation facilities
(c) early yielding rice variety
(d) disease resistant rice variety.
Answer. C

Question. To isolate protoplast, one needs 
(a) pectinase
(b) cellulase
(c) both pectinase and cellulase
(d) chitinase
Answer. C

NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production Assertion-Reason Questions

In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

Question. Assertion : Beehives are kept in closed farms throughout the year.
Reason : Bees are pollinating agents.
Answer. D

Question. Assertion : Micropropagation has been used to introduce variations in the offsprings.
Reason : Virus-free plants can be generated by the technique of micropropagation.
Answer. D

Question. Assertion : Single cell proteins (SCP) can help to meet increasing demands of growing population.
Reason : SCP is produced using low cost substrates, in high amount commercially.
Answer. A

Question. Assertion : Somatic embryos can be induced from any cell in plant tissue culture.
Reason : Any living plant cell is capable of differentiating into somatic embryos.
Answer. A

Question. Assertion : Fish meal is a rich source of protein for cattle and poultry.
Reason : Fish meal is produced from non-edible parts of fishes like fins, tail.
Answer. C

Question. Assertion : A major advantage of tissue culture is protoplast fusion.
Reason : A hybrid is formed by the fusion of naked protoplasts of two plants.
Answer. B

Question. Assertion : Inbreeding depression can be overcome by a single outcross.
Reason : Milk productivity can be increased by outcrossing method.
Answer. B

Question. Assertion : In plant tissue culture, somatic embryos can be induced from any plant cell.
Reason : Any viable plant cell can differentiate in to somatic embryos.
Answer. A

Question. Assertion : In emasculation male parts of the flower are removed.
Reason : There is no need to cover emasculated flowers.
Answer. C

Question. Assertion : Hisardale is cross breed of sheep.
Reason : Hisardale is developed by crossing Bikaneri ewe and Merino ram.
Answer. A

NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production Case-based/Source-based Question

1. Given below is a flowchart for the formation of somatic hybrid, Pomato.

Question. A certain tissue, of a plant, infected with TMV was used to obtain a new plant using tissue culture technique. Identify the technique used and reason out the possibility of obtaining a new healthy plant.
Answer. The technique used is tissue culture using meristematic tissue as this method produces virus free plants.

Question. How can pollen grains of wheat and rice which tend to lose viability within 30 minutes of their release be made available months later for breeding programmes?
Answer. The pollen grains can be stored in liquid nitrogen (−196°C). Such stored pollen grains do not lose their viability for years and can be used in breeding programmes.

Question. What is protoplast fusion?
Answer. The merging of protoplasts obtained from two different cells to form a hybrid protoplast is called protoplast fusion.

2. Study the table of varieties of crops shown resistance to certain diseases and answer the questions.
      rop disease                Disease resistant variety of crop
(a) White rust                   Pusa Swarnim
(b) Leaf and stripe rust      Himgiri
(c) Black rot                     Pusa Shubhra
(d) Jassids                        Pusa Sem 2

Question. Genetic variability is the root of any breeding programme. How does this variation occur?
Answer. (a) All the wild varieties and relatives of the cultivated crops are collected and preserved.
(b) For their characteristics, evaluation of these genetic collections are done.

Question. State the importance of biofortification.
Answer. (a) Breeding of crops for improvement of nutritional quality.
(b) Higher level of vitamins/proteins/minerals/healthier fats. (Any one)

Question. How is it possible to recover healthy banana plants from a diseased but desirable quality banana plant? Explain.
Answer. Healthy bananas can be obtained by tissue culture technique. The meristem (apical and axillary) is free from virus. Hence, it is removed and grown in vitro to obtain healthy banana.

3. Study the flow chart given below:
Cow is administrated with FSH hormone
   ↓
(1)
   ↓
6–8 eggs per cycle are derived
   ↓
Artificially inseminated
   ↓
Fertilised eggs at 8–32 cells are recovered
   ↓
(2)

Question. Identify the events that take place at stages (1) and (2) respectively.
Answer. Events taking place at:
Stage (1) — Follicular maturation (super-ovulation)
Stage (2) —Transfer to surrogate mothers

Question. State the importance of the technology explained above.
Answer. Due to this technology, high milk-yielding breeds of cows and high quality meat yielding bulls have been bred successfully to increase herd size in a short time. 

Question. Write one advantage of Artificial insemination.
Answer. It is healthier and cannot spread contagious diseases.

NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production Very Short Answer Questions

Question. Identify two correct statements from the following: 
(i) Apiculture means apical meristem culture.
(ii) Spinach is iron-enriched.
(iii) Green revolution has resulted in improved pulse-yield.
(iv) Aphids cannot infest rapeseed mustard.
Answer. (ii) and (iv) are correct.

Question. A herd of cattle is showing reduced fertility and productivity. Provide one reason and one suggestion to overcome this problem. 
Answer. Inbreeding depression or continuous inbreeding may be the reason of reduced fertility and productivity. To overcome this, the cattle should be mated with unrelated superior cattle of the same breed.

Question. Name the technology which in addition to tissue culture techniques play a pivotal role in enhancing food production.
Answer. Somatic hybridisation, Multiple Ovulation Embryo Transfer Technology

Question. Why is mutation breeding necessary for producing disease resistance varieties? 
Answer. Because there is limited availability of disease resistance genes in the crop plants and their wild relatives.

Question. What can be used as the reference material for comparison of any new improved variety?
Answer. The best available local cultivar.

Question. Which of the following is the semi-dwarf wheat that is high yielding and disease resistant?
Pusa Shubra, Kalyan sona, Ratna 
Answer. Kalyan sona

Question. Write the names of two semi-dwarf and high yielding rice varieties developed in India after 1966. 
Answer. Jaya, Ratna.

NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production Short Answer Questions

Question. Differentiate between inbreeding and heterosis. What is inbreeding depression?
Answer. Differences between inbreeding and heterosis
Inbreeding 
The cross between two individuals of a species that are related by descent is called inbreeding.
Heterosis
The cross between two unrelated individuals or species or genus may develop an improved hybrid called heterosis.
The loss of vigour/fertility and productivity due to continuous inbreeding especially close inbreeding is called inbreeding depression.

Question. Success rate of artificial insemination in cattle is fairly low. Identify any other mean to improve the successful production of hybrids. State the advantages of this technique.
Answer. Multiple Ovulation Embryo Transfer (MOET) technology can be used to improve production of hybrids. This technique produces 8-10 eggs at a time and the genetic mother is only available for superovulation. By this technique, herd size can be increased in a short time.

Question. How is outcrossing different from cross breeding? 
Answer. Outcrossing is the practice of mating animals of the same breed that have no common ancestors on either side of their pedigree up to 4-6 generations whereas cross breeding is the cross of one with superior females of another breed.

Question. Identify A, B, C and D in the table given below.

Answer. A : Himgiri B : Cauliflower
C : Bacterial blight D : White rust

Question. How has mutation breeding helped in improving the production of mung bean crop?
Answer. Mutation breeding has helped in the production of disease resistant varieties of mung bean crops against yellow mosaic virus and powdery mildew.

Question. Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology.
Answer. Steps for producing disease resistant plants are:
(i) Screening of germplasm (for resistance sources)
(ii) Hybridisation of selected parents
(iii) Selection and evaluation of hybrids (for disease resistance and high yields)
(iv) Testing and release of new varieties