Please see Chapter 9 Strategies for Enhancement in Food Production Exam Questions Class 12 Biology below. These important questions with solutions have been prepared based on the latest examination guidelines and syllabus issued by CBSE, NCERT, and KVS. We have provided Class 12 Biology Questions and answers for all chapters in your NCERT Book for Class 12 Biology. These solved problems for Strategies for Enhancement in Food Production in Class 12 Biology will help you to score more marks in upcoming examinations.
Exam Questions Chapter 9 Strategies for Enhancement in Food Production Class 12 Biology
Very Short Answer Questions
Question. Which of the following is the semi-dwarf wheat that is high yielding and disease resistant? Pusa Shubra, Kalyan sona, Ratna
Ans. Kalyan sona
Question. Write the name of the following:
(a) The most common species of bees suitable for apiculture.
(b) An improved breed of chicken.
Ans. (a) Apis indica/Apis mellifera/Apis dorsata
(b) Leghorn/Rhode island red/Minorca.
Question. Name any two diseases the ‘Himgiri’ variety of wheat is resistant to.
Ans. Leaf and stripe rust; Hill bunt
Question. What is meant by the term ‘breed’? What are the objectives of animal breeding?
Ans. 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. What is meant by ‘hidden hunger’?
Ans. Consumption of food deficient in nutrients particularly, micronutrients, proteins and vitamins is called hidden hunger.
Short Answer Questions
Question. What is inbreeding depression? Why do the self-pollinated crops not show the ill effects of inbreeding depression?
Ans. The continuous inbreeding may lead to reduced fertility and productivity called inbreeding depression. Self-pollinated crop does not show the ill effects of inbreeding depression because the deleterious allele becomes homozygous and exhibits their lethal effect so it is eliminated by selection.
Question. Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology.
Ans. 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.
Question. Name the methods employed in animal breeding. According to you which of the methods is best? Why?
Ans. 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. How are biofortified maize and wheat considered nutritionally improved?
Ans. Biofortified maize has twice the amount of amino acids, lysine and tryptophan, compared to existing hybrids and the wheat variety has increased protein content.
Question. Differentiate between inbreeding and heterosis. What is inbreeding depression?
Ans. Table 9.7: Differences between inbreeding and heterosis
| Inbreeding | Heterosis |
| The cross between two individuals of a species that are related by descent is called inbreeding. | 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. Write the importance of bagging of unisexual flowers in crop improvement programme.
Ans. 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.
Question. What are the major advantages of producing plants by micropropagation?
Ans. 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. Identify ‘A’, ‘B’, ‘C’ and ‘D’ in the given table.
Ans.
| Crop | Variety | Resistance to disease |
| A | Himgiri | Leaf rust |
| Cauliflower | Pusa Shubhra | B |
| Brassica | Pusa Swarnim | C |
| Cowpea | D | Bacterial blight |
Question. Keeping beehives in crop fields has several advantages. List any two.
Ans. (i) Pollination management
(ii) Versatile use of resources
(iii) Honey production at no cost
Question. (a) Why are the plants raised through micropropagation termed as somaclones?
(b) Mention two advantages of this technique.
Ans. (a) Plants raised through micropropagation are genetically identical, hence the name somaclones.
(b) (i) Large number of plants are produced in short duration.
(ii) Virus-free plants are produced.
Question. (i) Mention the property that enables the explants to regenerate into a new plant.
(ii) A banana herb is virus-infected. Describe the method that will help in obtaining healthy banana plants from this diseased plant.
OR
How is it possible to recover healthy banana plants from a diseased but desirable quality banana plant? Explain.
Ans. (i) Totipotency is the ability of a cell to grow or generate the whole plant.
(ii) Healthy banana plants can be obtained from diseased plants by meristem culture. Although the plant is virus infected, the apical and axillary meristem is free of virus. The meristem is removed from the plant and grown in vitro by micropropagation. The plants produced are virus-free.
Question. Explain the advantage of cross-breeding of the two species of sugarcane in India.
Ans. Saccharum barberi, grown in north India, had poor sugar content and yield, whereas Saccharum officinarum, grown in south India, had thicker stem and higher sugar content. The sugarcane species obtained after cross breeding these two species had thick stems, high sugar, high yield and ability to grow in north India.
Question. How does culturing Spirulina solve the food problems of the growing human population?
OR
“Large scale cultivation of Spirulina is highly advantageous for human population.” Explain giving two reasons.
Ans. Microbes are being grown on an industrial scale as source of good protein. Microbes like Spirulina can be grown easily on materials like waste water from potato processing plants (containing starch), straw, molasses, animal manure and even sewage, to produce large quantities and can serve as food rich in protein, minerals, fats carbohydrate and vitamins. Incidentally such utilisation also reduces environmental pollution and hence is environment friendly.
Long Answer Questions
Question. What is inbreeding depression and how is it caused in organisms? Write any two advantages of inbreeding.
Ans. 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. Differentiate between inbreeding and outbreeeding in cattle. State one advantage and one disadvantage for each one of them.
Ans.
| S. No. | Inbreeding | Outbreeding |
| (i) | It is breeding between animals belonging to same breeds. | It is breeding between different breeds of animals. |
| (ii) | Advantage: Helps in accumulation of superior genes. | Advantage: Helps overcoming inbreeding depression. |
| (iii) | Disadvantage: Reduces fertility/productivity. | Disadvantage: There is a possibility of introduction of undesirable characters. |
Question. Why is it necessary to emasculate a bisexual flower in a plant breeding programme? Mention the condition under which emasculation is not necessary.
Ans. 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. 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.
Ans. 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) What is the programme called that is involved in improving success rate of production of desired hybrid and herd size of cattle?
(b) Explain the method used for carrying this programme for cows.
Ans. (a) Multiple ovulation embryo transfer method/MOET.
(b) Refer to Basic Concepts Point 10 (Procedure).
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.
Ans. (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.
