CBSE Class 12 Biology Strategies for Enhancement In Food Production Worksheet Set B

Important Questions for NCERT Class 12 Biology Strategies for Enhancement in Food Production

Question. Which variety of Bhindi is resistance to shoot and fruit borer ?
(a) Pusa Gaurav
(b) Pusa sem-2
(c) Pusa komal
(d) Pusa sawani

Answer : D

Question. The entire collection of plants / seeds having all the diverse alleles for all genes in a given crop is known as
(a) Genetic erosion
(b) Germplasm collection
(c) Gene pool
(d) Genetic drift

Answer : B

Question. For how many growing seasons, new selected lines is tested in farmer's field
(a) Two growing seasons
(b) Three growing seasons
(c) Four growing seasons
(d) Five growing seasons

Answer : B

Question. Which of the following can be used for cultivation of SCP
(a) Waste water from potato processing plants
(b) Straw
(c) Sewage
(d) All above

Answer : D

Question. 250 gm Methylophilus methylotrophus can produce how much amount of proteins in a day :-
(a) 2.5 tonnes
(b) 25 tonnes
(c) 250 tonnes
(d) 25 Kg

Answer : B

Question. Which character of maize leads to resistance to maize stem borers naturally ?
(a) High aspartic acid
(b) Low nitrogen content
(c) Low sugar content
(d) All of the above

Answer : D

Question. "Atlas 66" is high protein contained variety of :
(a) Wheat
(b) Maize
(c) Rice
(d) Bhindi

Answer : A

Question. Which of the following rice variety were developed in India
(a) IR - 8
(b) IR - 36
(c) TN - 1
(d) Jaya

Answer : D

Question. Which of the following sugarcane species were crossed to combine desirable qualities of high yield, thick stem, high sugar content and ability to grow in sugarcane areas of North India
(a) Saccharum officinale x Saccharum barberi
(b) S. officinarum x S. baberi
(c) S. barberi x S.indica
(d) S. officinarum x S. officinale

Answer : B

Question. Match the following
A. Himgiri variety i. White rust
B. Pusa swarnim ii. Hill bunt
C. Pusa shubhra iii. Leaf curl
D. Pusa sadabahar iv. Black rot
A B C D
(a) ii i iii iv
(b) i ii iv iii
(c) ii i iv iii
(d) i ii iii iv

Answer : C

Question. In maize resistance to maize stem borer is due to
(a) High aspartic acid
(b) Low nitrogen and sugar content
(c) High nitrogen and suger content
(d) Both 1 and 2

Answer : D

Question. Select the incorrect match
(a) Pusa gaurav - Aphids
(b) Pusa sem 2 - Shoot borers
(c) Pusa sem 3 - Jassids & Aphids
(d) Pusa sawani - Fruit borers

Answer : B

Question. Hidden hunger is associated with deficiency of
(a) Proteins
(b) Vitamins
(c) Micronutrients
(d) All the above

Answer : D

Question. Which of the following is not a consiquence of hidden hunger
(a) Increased the risk of disease
(b) Reduced life span
(c) Reduced mental abilities
(d) Reduced skin pigmentation

Answer : D

Question. Breeding crops with higher levels of vitamins andmin erals, higher proteins and healthier fats is known as
(a) Bioremediation
(b) Biomagnification
(c) Biofortification
(d) Biotransformation

Answer : C

Question. Himgiri variety of wheat, which developed by hybridisation and selection is mainly resistance for
(a) Leaf and stripe rust
(b) White rust
(c) Bacterial blight
(d) Chilly mosaic virus

Answer : A

Question. The conventional method of breeding for disease resistance in plants is :
(a) Hybridisation
(b) Selection
(c) Mutation
(d) Both (a) and (b)

Answer : D

Question. Which of the following wheat variety have high protein content
(a) Kalyansona
(b) Sharbati sonaro
(c) Atlas 66
(d) IR - 8

Answer : C

Question. Biofortified rice are enriched in which of the following nutrient
(a) Iron
(b) Amino acids
(c) Fatty acids
(d) Essential amino acids

Answer : A

Question. Which of the following cell property is the basis of plant tissue culture
(a) Homeostasis
(b) Thermoperiodicity
(c) Meristematic
(d) Totipotency

Answer : D

Very Short Answer Types Questions

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

Question. Why is it easier to culture meristems compared to permanent tissues?
Answer : Meristems have the capacity to divide continuously throughout their life. Their walls are thin and elastic to facilitate the division, hence are suitable for tissue culture. Permanent cells lose their ability to divide and their walls are thick. They have to differentiate to divide, hence are not easier to culture.

Question. Interspecific crosses are rare in nature and intergeneric crosses almost unknown. Why?
Answer : In interspecific crosses, male and female animals of two different related species are mated. In some cases, the progeny may combine desirable features of both the parents, and may be of considerable economic value, e.g., the mule. An interspecific hybrid’s fertility varies. Many of Panthera (ligers, tigons leopons etc.) hybrid males are infertile, while the female counterparts can breed with the species she contains (female ligers can breed with a lion or a tiger to produce li-ligers or ti-tigers). These are rare in nature. Intergeneric hybridisation is the crossing of two different animals/plants of different genus. It is almost unknown in nature. Intergeneric hybrids more or less never form complete zygotes/embryos. These are sterile/infertile.

Question. Differentiate between pisciculture and aquaculture.
Answer : Fish farming in isolated water bodies is called pisciculture. Similarly, when culturing of aquatic plants and animals is done in freshwater bodies, it is called aquaculture.

Question. What are the duties of a veterinary doctor in management of a poultry farm?
Answer : A veterinary doctor has to ensure proper and safe farm conditions to keep the animals disease-free and treat them appropriately if diseased.

Question. In animal husbandry, if two closely related animals are mated for a few generations, it results in loss of fertility and vigour. Why is this so?
Answer : The loss in fertility and vigour occurs after inbreeding because the recessive alleles tend to get together and express harmful effects in the progeny.

Question. In the area of plant breeding, it is important not only to preserve the seeds of the variety being cultivated, but also to preserve all its wild relatives. Explain with a suitable example.
Answer : Collection and preservation of all the different wild varieties, species and relatives of the cultivated species is a important for effective exploitation of natural genes available in the population. e.g., sources of resistance genes may be cultivated varieties, germplasm collections of the crop or wild relatives.

Question. Would it be wrong to call plants obtained through micro-propagation as ‘clones’? Comment.
Answer : No, it is not wrong to call plants obtained through micro-propagation as clones because each of these plants will be genetically identical to each other and the parent plant.

Question. How is a somatic hybrid different from a hybrid?
Answer : Somatic hybrids are obtained by uniting protoplasts from two different varieties of plants and then further cultured to form a novel plant. Compatibility between two plants is not a limitation. Any two protoplasts can be united. Whereas, hybrids are obtained by crossing two selected parent plants of opposite sex. Many times compatibility is a limitation for breeding.

Question. What is emasculation? Why and when is it done?
Answer : Removal of stamens from the bisexual flower that is used as a female parent in plant hybridisation is called emasculation. This is done to avoid unwanted self-pollination. This has to be done at bud condition before the anthers dehisce.

Question. Discuss the two main limitations of plant hybridisation programme.
Answer : The limitations of plant hybridisation programme include
(i) Availability of a limited number of identified disease resistant genes that are present in various crop varieties or wild relatives.
(ii) Compatibility of parents.
(iii) Time consuming and tedious process.

Short Answer Type Questions

Question. A farmer was facing the problem of low yield from his farm. He was advised to keep a beehive in the vicinity. Why? How would the beehive help in enhancing yield?
Answer : Bee keeping or apiculture is an important enterprise of agriculture concerned with the maintenance of hives of honeybees for the commercial production of honey and wax. Bee keeping is a low investment, less problematic and highly profitable cottage industry. The beehives when kept in the fields of sunflower, Brassica, apple and pear, increase the pollination efficiency of flowering plants and improve the yields.

Question. Life style diseases are increasing alarmingly in India. We are also dealing with large scale malnutrition in the population. Is there any method by which we can address both of these problems together?
Answer : To address both these problems biofortification can be done. This area focuses at improving food quality with respect to protein, oil, vitamin, micronutrient and mineral content. The oils need to be rich in omega 3 fatty acids which are good for heart. Similarly, proteins should have more of lysine and tryptophan (essential amino acids). Many varieties of maize, carrots and spinach have been released which fulfill the above criteria.

Question. It is easier to culture plant cells in vitro as compared to animal cells. Why?
Answer : 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 a new plant. This property of plant cell is termed as totipotency. This ability is limited in animal cells.

Question. The culture medium (nutrient medium) can be referred to as a ‘highly enriched laboratory soil’. Justify the statement.
Answer : 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.

Question. It is said, that diseases are spreading faster due to globalisation and increased movement of people. Justify the statement taking the example of H 5N1 virus.
Answer : The avian flu (bird flu) is a current and significant issue involving the global environment as well as the health of millions of people around the world. The H N 5 1 virus (influenza-A) occurs mainly in birds, is highly contagious among them and can be deadly. The major global environmental issue that plays a large role in the advancement of the H N 5 1 avian influenza virus is globalisaiton. i.e., increasing integration of countries. Through globalisation, the progression of the H N 5 1 avian influenza virus occur through the world at a pace faster than scientists can anticipate, and also technology and research cannot possibly keep up. Globalisation will give theH N 5 1 avian influenza virus an opportunity to travel to various parts of the world without impediment. Once, it has developed the ability to spread easily from human to human, the major concern becomes the travel of individuals around the world, particularly air travel. Through air travel, an infected individual could infect dozens of people during their movement, those newly infected individuals would in turn, infect dozens more, and so on and so forth.

Question. Explain the concept of the blue revolution.
Answer : The term ‘Blue Revolution’ refers to the remarkable emergence of aquaculture as an important and highly productive agricultural activity. Aquaculture refers to all forms of active culturing of aquatic animals (including fish) and plants, occuring in marine, brackish or freshwater.

Question. Is there any relationship between dedifferentiation and the higher degree of success achieved in plant tissue culture experiments?
Answer : 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.

Question. Give me a living cell of any plant and I will give you a thousand plants of the same type”, Is this only a slogan or is it scientifically possible? Write your comments and justify them.
Answer : It is scientifically possible to grow thousand plants from a living cell of any plant and this process is called micropropagation. The property of 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 generations. Micropropagation is widely used in forestry and in floriculture. Plants can be obtained throughout the year under controlled conditions.

Question. Define the term ‘stress’ for plants. Discuss briefly the two types of stress encountered by plants.
Answer : 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.

Question. Discuss natural selection and artificial selection. What are the implications of the latter on the process of evolution?
Answer : Natural selection is a gradual, non-random process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism to evolution. 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 with 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.

Long Answer Type Questions

Question. What are the advantages of tissue culture methods over conventional method of plant breeding in crop improvement programmes?
Answer : As traditional (conventional) breeding methods failed to keep pace with demand and to sufficiently provide fast and efficient systems for crop improvement, another technology called tissue culture developed. The advantages of tissue culture over conventional breeding are as follows
(i) It can be used to produce large number of plantlets within a short period by micropropagation.
(ii) All cells in the culture are derived from a single explant by mitotic division, therefore all have the similar genotype and constitute a clone.
(iii) 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. (iv) Virus free plantlets can be obtained by meristem culture.
(v) Embryos which do not survive inside seeds can be grown by tissue culture to form new plants.

Question. ‘Modern methods of breeding animals and plants can alleviate the global food shortage’. Comment on the statement and give suitable examples.
Answer : With ever increasing population of the world, enhancement of food production is a major necessity. Modern biological principles as applied to animal husbandry and plant breeding have a major role in our efforts to increase food production. These modern techniques include embryo transfer technology and tissue culture techniques. Multiple Ovulation Embryo Transfer Technology (MOET) is a programme for herd improvement in animals like cattle, sheep, rabbits, buffaloes, mares, etc. High milk-yielding breeds of female are bred with high quality meat-yielding (meat with less lipid) bulls to increase herd size. 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
(i) A cow is administered hormones with FSH-like activity to induce follicular maturation and super-ovulation.
(ii) The cow produces 6-8 eggs instead of one egg produced normally.
(iii) It is now, either mated with an elite bull or artificial insemination is carried out.
(iv) When the fertilised eggs attain 8-32 cells stage, they are non-surgically removed and transferred to a surrogate mother.
(v) The genetic mother can now be again super ovulated. Modern methods in plant breeding involves following
(i) 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.
(ii) Biofortification is the method for developing crops with higher levels of vitamins, minerals, proteins and healthier fats to improve public health.
(iii) Single cell protein is an alternative protein source for animal and human nutrition from certain beneficial microorganisms like Spirulina.

Question. Does apiculture offer multiple advantages to farmers? List its advantages if it is located near a place of commercial flower cultivation.
Answer : Yes, apiculture offers many advantages to farmers such as
(i) Honey produced by honeybees is a food of high nutritive value.
(ii) It is used in the indigenous system of medicine.
(iii) Honeybee also produces beeswax, which is used in the preparation of cosmetics 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
(i) Increases pollination efficiency.
(ii) Improves the yield which is beneficial both from the point of view of crop yield and honey yield.

Question. What are three options to increase food production? Discuss each giving the salient features, merits and demerits.
Answer : 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 Proteins
(i) Its production reduces pollution as it uses organic wastes and industrial effluents.
(ii) It provides a protein-rich diet.
(iii) It fulfills the demand of protein for human diet and takes off the pressure on agriculture system. Demerits of Single Cell Protein
(i) Sometimes the microbial biomass when taken as diet supplement may lead to allergic reactions.
(ii) Many 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
(i) It can increase yields grown on the same or less acreage.
(ii) It can potentially improve nutritional value or other health benefits. Demerits of Biofortification
(i) Its successful implementation into society requires safe delivery systems, stable policies, appropriate social infrastructures.
(ii) It continued by financial support also.
(c) Tissue-Culture It is an in vitro 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
(i) A large number of plants can be grown in short time.
(ii) Disease-free plants can be multiplied.
(iii) Seedless plants can be multiplied
(iv) The plants where sexual reproduction is absent may undergo somatic hybridisation.
Demerits of Tissue Culture
(i) It requires great expense because it needs latest techniques in the laboratory.
(ii) It requires acclimatisation of plants grown by tissue culture to the external environment.
(iii) It requires special expertise.

Question. What is inbreeding depression and how is it caused in organisms? Write any two advantages of inbreeding.
Answer : Animal inbreeding has the following advantages:
(i) It helps in evolving the pure lines of animals.
(ii) It helps in accumulation of superior genes and elimination of less desirable genes.
(iii) There is an increase in productivity in the inbred population.
Inbreeding depression stands for the inability of an organism to reproduce. It occurs due to continued inbreeding especially close inbreeding. There is reduction in fertility and productivity of the population that is inbred continuously.

Question. (a) Explain how to overcome inbreeding depression in cattle. 
(b) List three advantages of inbreeding in cattle.
(c) Name an improved breed of cattle.
Answer : (a) In order to overcome the cattle from inbreeding depression, selected animals of the breeding population should be mated with unrelated superior animals of the same breed or different breed. This helps in restoring the fertility and yield in the cattle.
(b) (i) Pure lines can be obtained.
(ii) Harmful recessive genes are exposed that are eliminated by selection.
(iii) Superior genes can be accumulated by inbreeding by eliminating undesirable genes.
(c) Jersey cow.

Question. Mention the cause and effect of inbreeding depression in cattle. How can it be overcome?
Explain.
Answer : Inbreeding which refers to the mating between closely related individuals with the same breed for 4–6 generations causes inbreeding depression. Continued inbreeding, especially close inbreeding usually reduces the fertility and even productivity of the organism, this is called as inbreeding depression.
It can be overcome by mating the selected animals of breeding population with unrelated superior animals of same breed or different breed to restore fertility and yield.

Question. Explain the importance of “selection” during inbreeding in cattle.
Answer : Selection during inbreeding helps in accumulation of superior genes and elimination of less desirable genes. It increases homozygosity, pure lines, true breeding and helps to restore fertility.It also helps to increase yield or productivity. The cattle produces more milk per lactation, produces superior progeny and produces disease resistant breeds.

Question. (a) Name the Indian scientist whose efforts brought ‘green revolution’ in India.
(b) Mention the steps that are essentially carried out in developing a new genetic variety of crop under plant breeding programme.
Answer : (a) M.S. Swaminathan brought green revolution in India.
(b) The steps are:
(i) Collection of variability.
(ii) Evaluation and selection of parents.
(iii) Cross hybridisation among the selected parents.
(iv) Selection and testing of superior recombinants.
(v) Testing, release and commercialisation of new cultivars.

Question. Name the technique and the property of plant cells that can help to grow somaclones of certain desired variety of apple. Explain how somaclones of apple can be obtained in the lab so as to get the desired variety on a large scale. 
Answer : Tissue Culture or micropropagation can help grow somaclones because of the property of totipotency in plant cells.
Explants of apple plant (any small part) is taken and grown in a test tube under sterile conditions in (special) nutrient media. The nutrient media contains sucrose, inorganic salts, amino acids and vitamins, with growth regulators.

Question. (a) What is micropropagation? Why are the plants produced by micropropagation called somaclones?
(b) Name the technique by which healthy plants can be recovered from the diseased plants.
Answer : (a) Micropropagation is the method of growing a number of plants through tissue culture. Since tissue culture involves only mitotic divisions, the plantlets formed are genetically identical and hence are called somaclones.
(b) Meristem culture.

Question. Explain the process of artificial hybridisation to get improved crop variety in (i) plants bearing bisexual flowers (ii) female parent producing unisexual flowers. 
Answer : (i) In plants bearing bisexual flowers, the anthers are removed from the flower before they dehisce. This is called emasculation. The emasculated flowers are covered with a bag of butter paper to prevent contamination of stigma with unwanted pollen. This process is called bagging. When this stigma attains receptivity, mature pollen grains are dusted on the stigma and the flowers are rebagged to allow the fruits to develop.
(ii) If the female parent produces unisexual flowers, there is no need of emasculation. The flower buds are bagged before the flowers open. When the stigma becomes receptive, pollen is dusted on stigma and the flower is rebagged.

Question. IARI has released several varieties of crop plants that are biofortified. Give three examples of such crops and their biofortifications.
Answer : (i) Bittergourd enriched with vitamin C.
(ii) Carrots enriched with vitamin A.
(iii) Spinach enriched with iron and calcium.

Question. (a) Write the desirable characters a farmer looks for in his sugarcane crop.
(b) How did plant breeding techniques help north Indian farmers to develop cane with desired characters? 
Answer : (a) The desirable characters for a sugarcane crop are high yield, thick stem, high sugar content and ability to grow in their areas.
(b) Saccharum barberi had poor sugar content and yield but Saccharum officinarum had thicker stems and higher sugar content but it could not be grown in northern India. By crossing Saccharum officinarum, the south Indian variety with Saccharum barberi, the north Indian low yield variety, the farmers developed cane having desired characteristics.

Question. Differentiate between somaclones and somatic hybrids. Give one example of each.
Answer : 

Question. Differentiate between inbreeding and outbreeeding in cattle. State one advantage and one disadvantage for each one of them.
Answer : Differences between inbreeding and outbreeding

Question. Why is it necessary to emasculate a bisexual flower in a plant breeding programme? Mention the condition under which emasculation is not necessary. 
Answer : Emasculation is necessary to ensure that only the desired pollen grains are used for pollination and the stigma is protected from contamination, from unwanted self pollen. The anthers are removed followed by bagging so the plant now behaves as a female plant. The pollen grains from the anthers of the desired male plant can be dusted on the stigma of flower of the female plant to obtain desired results.
Emasculation is not required if the plant produces unisexual flowers.

Question. (a) Write the two limitations of traditional breeding technique that led to promotion of micropropagation.
(b) Mention two advantages of micropropagation.
(c) Give two examples where it is commercially adopted. 
Answer : (a) (i) Failed to keep pace with demand.
(ii) Failed to provide fast and efficient system of crop improvement.
(b) (i) Large number of plants can be developed in a short duration.
(ii) Production of genetically identical plants or somaclones.
(iii) Healthy plants can be recovered from diseased plants. (Any two)
(c) Tomato, banana, apple. (Any two)

Question. Mention the property of plant cells that has helped them to grow into a new plant in in vitro conditions. Explain the advantages of micropropagation. 
Answer : The property of plant cells that helped them to grow into a new plant is totipotency.
The advantages of micropropagation are:
(i) It is possible to achieve propagation of a large number of plants in very short durations.Plants like tomato, banana, apple, etc., have been produced on commercial scale.
(ii) 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, sugar cane, potato, etc.

Question. How can crop varieties be made disease-resistant to overcome food crisis in India? Explain.
Name one disease-resistant variety in India of:
(a) Wheat to leaf and stripe rust.
(b) Brassica to white rust. 
Answer : Crop varieties can be made disease-resistant by conventional breeding methods or by mutation breeding. The germplasm is screened for resistance sources or mutations are introduced, followed by hybridisation of selected parents. The resulting hybrids are evaluated and tested. Finally,disease-resistant varieties are released.
Disease-resistant variety of:
(a) Wheat to leaf and stripe rust—Himgiri.
(b) Brassica to white rust—Pusa swarnim.

Question. (a) “Fortification of crops is the need of the hour.” Give two reasons.
(b) Select one fresh water and one marine fish from the following:
Prawn; Catla; Mackerel; Lobster 
Answer : Fortification of crops is needed for following reasons:
(a) (i) To improve the nutritional quality,
(ii) to improve public health,
(iii) to prevent malnutrition, (Any two)
(b) Fresh water : Catla
Marine fish : Mackerel.

Question. According to Global Hunger Index, 2014, two billion people suffer from hidden hunger.
Apply your knowledge of plant breeding techniques to suggest a programme to improve public health. Specify four objectives of the programme. Also, mention one example of such a produce. 
Answer : Biofortification can improve public health. It involves breeding crops with higher levels of vitamins and minerals, or higher protein and healthier fats.
Breeding for improved nutritional quality is improving:
(i) Protein content and quality;
(ii) Oil content and quality;
(iii) Vitamin content; and
(iv) Micronutrient and mineral content.
In the year 2000, maize hybrids that had twice the amount of the amino acids, lysine and tryptophan, compared to existing maize hybrids were developed. Another example is the wheat variety, Atlas 66, having a high protein content which has been used as a donor for improving cultivated wheat.

Question. (a) State the objective of animal breeding.
(b) List the importance and limitations of inbreeding. How can the limitations be overcome?
(c) Give an example of a new breed each of cattle and poultry.
Answer : (a) Objective of animal breeding is to increase the yield of animal and improve the desirable qualities of the produce.
(b) Importance:
(i) Increases homozygosity
(ii) Evolves pure line
(iii) Expose harmful recessive genes
(iv) Help in accumulation of superior genes
(v) Eliminate less desirable genes.
Limitations:
Inbreeding reduces fertility and productivity (inbreeding depression).
The limitations can be overcome by outbreeding or out-crossing or interspecific hybridisation.
Selected animals may be bred with unrelated superior animals of the same breed.
(c) Hisardale is a new breed developed by crossing Bikaneri ewes and Mirano rams (sheep) and Leghorn is the new breed of chicken and Jersey is improved breed of cattle..

Question. (i) Name the tropical sugarcane variety grown in South India. How has it helped in improving the sugar cane quality grown in North India?
(ii) Identify ‘a’, ‘b’ and ‘c’ in the following table:
No.    Crop           Variety             Insect Pests
1.     Brassica      Pusa Gaurav            (a)
2.     Flat Bean    Pusa Sem 2             (b)
                           Pusa Sem 3
3.     (c)               Pusa Sawani        Shoot and Fruit borer
                           Pusa A-4
Answer : (i) Saccharum officinarum is grown in South India. It was crossed with North Indian variety (Saccharum barberi) to combine the desirable qualities of high yield, thick stems high sugar and ability to grow in North India.
(ii) (a) Aphids
(b) Jassids/aphids/fruit borer
(c) Okra (Bhindi).

Question. (a) Name the technology that has helped the scientists to propagate on large scale the desired crops in short duration. List the steps carried out to propagate the crops by the said technique.
(b) How are somatic hybrids obtained?
Answer : (a) The technology that has helped the scientists to propagate on large scale the desired crops is tissue culture or micropropagation.
The steps to propagate crops are:
(i) Obtaining an explant from a plant.
(ii) Growing the explant in a test tube under sterile conditions.
(iii) A special nutrient or culture medium is provided for growth.
(b) Isolated single cells are isolated from plants. Their cell walls are digested to obtain protoplasts.
Isolated protoplasts from two different plant varieties are fused to get hybrid protoplasts.

Question. With advancements in genetics, molecular biology and tissue culture, new traits have been incorporated into crop plants.
Explain the main steps in breeding a new genetic variety of a crop.
Answer : (i) Collection of variability on germplasm collection. All different wild varieties, species and relatives of cultivated species are collected and preserved.
(ii) Evaluation and selection of parents to identify plant with desirable combination of character.
Pure lines are created.
(iii) Cross hybridisation among selected parents to produce hybrids.
(iv) Selection and testing of superior recombinants. Selection among the progeny of the hybrids that have desired character combinations, superior to both the parents are self pollinated for several generations.
(v) Testing, release and commercialisation of new cultivars. Newly selected lines are evaluated for yield and other agronomic traits of quality or disease resistance in research fields followed by testing the material in farmers fields for three seasons in different agroclimatic zones.

Question. Differentiate between an inbred line and a hybrid variety of crop. Explain the steps involved in the production of the hybrid variety.
Answer : Differences between inbred line and hybrid variety
Inbred line
The continuous inbreeding in a cross-pollinated crop develops a homozygous line called inbred line.
Hybrid variety
A hybrid variety is produced by crossing two different species where progeny obtained is used for raising the next seasonal crop.

ONE MARK QUESTION

1 List any two economically important products for humans obtained from Apis indica.

2 How are the two following varieties of sugarcane different from each other?

i) Saccharum barberi ii) Saccharum officinarum

3 Mention the strategy used to increase homozygosity in cattle for desired traits.

4 Which one of the following used in apiculture?

Hilsa, Apis indica, Sonalika

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

6 Define plant breeding.

7 Name the scientist who developed semi-dwarf varieties of wheat in Mexico.

8 Name two semi-dwarf varieties of wheat introduced into all wheat growing places of India.

9 Where was IR-8 developed?

10 Name two better yielding semi-dwarf varieties of rice developed in India.

TWO MARK QUESTIONS

11 MOET programme has helped in increasing the herd size of the desired variety of cattle. List the steps involved in conducting the programme.

12 Define inbreeding depression. How to overcome this?

13 Why is mutation breeding necessary for breeding for disease resistance?

14 What are SCPs? What is the significance of such a protein.

15 Which part of the plant is best suited for making virus-free plants and why?

16 What is meant by germplam collection? Why is it necessary? 

3 MARK QUESTIONS

17 What is meant by biofortification? Write the objectives of biofortification?

18 Define each of the following:

a) Tissue culture

b) Explants

c) somaclones

19 Give one example of disease caused by each of fungi, bacteria and viruses in crop plants.

5 MARK QUESTIONS

20 What is somatic hybridization? Explain the procedure. Mention any one use of somatic hybridization.

21 Briefly describe the steps involved in plant breeding.

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