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

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NCERT Solutions PDF Class 12 PDF

This chapter focuses on various strategies employed to enhance food production, a critical aspect of meeting global food demands. It delves into techniques like animal husbandry, plant breeding, and tissue culture, explaining how these methods contribute to improving crop yields and livestock quality. The solutions cover multiple-choice questions that test understanding of concepts such as inbreeding, disease resistance, and the development of new varieties. Students will learn about the scientific principles behind increasing food availability and quality through selective breeding, hybridization, and modern biotechnological approaches. These NCERT Solutions are designed to help students grasp the core concepts and prepare effectively for their board examinations by providing clear, step-by-step explanations.

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Quick info

BoardCBSE
ClassClass 12
SubjectBiology Exemplar
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 9

Chapter summary

Chapter 9 of the CBSE Class 12 Biology Exemplar Solutions focuses on 'Strategies for Enhancement in Food Production'. It covers key topics like animal husbandry, plant breeding methods, single-cell protein, tissue culture, and apiculture. The solutions provide detailed explanations for multiple-choice questions, helping students understand concepts like the benefits of inbreeding, the characteristics of different crop varieties, and the causes of plant diseases. This chapter is crucial for understanding how scientific interventions can significantly boost food availability and quality.

Learning outcomes

  • Understand the importance of enhancing food production.
  • Identify different breeds and varieties of animals and plants.
  • Explain the process and benefits of inbreeding in animal husbandry.
  • Recognize common plant diseases and their causes (fungal vs. bacterial).
  • Differentiate between various crop varieties and their characteristics.
  • Explain the role of meristematic tissues in virus-free plant propagation.

Topics covered

Paper topics

  • Animal Husbandry
  • Breeds and Breeding
  • Inbreeding
  • Plant Breeding
  • Improved Crop Varieties
  • Disease Resistance in Plants
  • Apiculture
  • Fisheries
  • Tissue Culture
  • Single Cell Protein
  • Meristem Culture
  • Plant Diseases

Important topics

  • Animal Husbandry and Breeding Strategies
  • Inbreeding and its Effects
  • Plant Breeding for Crop Improvement
  • Disease Resistance Mechanisms
  • Role of Meristem Culture
  • Improved Crop Varieties (e.g., Sonalika, Kalyan Sona)

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Questions and Solutions

Q. 1

The chances of contacting bird flu from a properly cooked (above 100° C) chicken and egg are
  1. very high
  2. high
  3. moderate
  4. None of these
Solution: The correct option is (d) None of these. Properly cooking chicken and eggs at temperatures at or above 70°C is sufficient to inactivate the avian influenza virus. While highly pathogenic strains can be present in infected birds and their eggs, the heat from proper cooking destroys the virus, making the risk of contracting bird flu negligible.

Q. 2

A group of animals which are related by descent and share many similarities are referred to as
  1. breed
  2. race
  3. variety
  4. species
Solution: The correct option is (a) breed. A breed is defined as a group of animals that are related by descent and share common similarities in characteristics such as general appearance, features, size, and body configuration. A 'race' is typically used for human classification, 'variety' often refers to plants, and 'species' is a broader biological classification.

Q. 3

Inbreeding is carried out in animal husbandry because it
  1. increases vigour
  2. improves the breed
  3. increases heterozygosity
  4. increases homozygosity
Solution: The correct option is (d) increases homozygosity. Inbreeding involves mating more closely related individuals within the same breed for several generations. This process increases homozygosity, meaning individuals become more genetically uniform. It is essential for developing a pure line in animals, as it helps in accumulating superior genes and eliminating harmful recessive genes through selection.

Q. 4

Sonalika and Kalyan Sona are varieties of
  1. wheat
  2. rice
  3. millet
  4. tobacco
Solution: The correct option is (a) wheat. Sonalika and Kalyan Sona are well-known, high-yielding, semi-dwarf varieties of wheat. They were developed at the Indian Agricultural Research Institute (IARI) and possess desirable traits like amber grains and good yield potential.

Q. 5

Which one of the following is not a fungal disease?
  1. Rust of wheat
  2. Smut of bajra
  3. Black rot of crucifers
  4. Red rot of sugarcane
Solution: The correct option is (c) Black rot of crucifers. This disease is caused by the bacterium Xanthomonas campestris, not a fungus. The other options listed are fungal diseases: Rust of wheat is caused by Puccinia, Smut of bajra by Tolyposporium penicillariae, and Red rot of sugarcane by Colletotrichum falcatum.

Q. 6

In virus-infected plants the meristematic tissues in both apical and axillary buds are free of virus because
  1. the dividing cells are virus resistant
  2. meristems have antiviral compounds
  3. the cell division of meristems are faster than the rate of viral multiplication
  4. viruses cannot multiply within meristem cell(s)
Solution: The correct option is (c) the cell division of meristems are faster than the rate of viral multiplication. Meristematic tissues, found in the actively growing regions of plants like apical and axillary buds, exhibit a very high rate of cell division. This rapid proliferation outpaces the rate at which viruses can multiply and spread, often resulting in the meristematic cells remaining free of viral infection. This property is utilized to produce virus-free plants through meristem culture.

Q. 7

Several South Indian states raise 2-3 crops of rice annually. The agronomic feature that makes this possible is because of
  1. shorter rice plant
  2. better irrigation facilities
  3. early yielding rice variety
  4. disease resistant rice variety
Solution: The correct option is (c) early yielding rice variety. The development and cultivation of rice varieties that mature quickly allow farmers to harvest multiple crops within a single agricultural year. This agronomic feature is crucial for achieving high productivity and enables regions like several South Indian states to raise 2-3 crops of rice annually, contributing significantly to food security.

Common mistakes

  • Confusing the terms 'breed', 'race', 'variety', and 'species'.
  • Misunderstanding the effect of inbreeding on homozygosity/heterozygosity.
  • Incorrectly identifying the causal agent (fungus vs. bacteria) of plant diseases.
  • Not recognizing the significance of early-yielding varieties for multiple cropping.

Revision tips

  • Focus on understanding the definitions of key terms like breed, variety, and inbreeding.
  • Memorize examples of improved crop varieties and their characteristics.
  • Pay close attention to the distinction between fungal and bacterial plant diseases.
  • Review the reasons why meristem culture is effective in producing virus-free plants.

Practice MCQs

Q1. What are the chances of contracting bird flu from properly cooked chicken and eggs (cooked above 100°C)?

Q2. A group of animals that are related by descent and share numerous similarities are known as:

Q3. In animal husbandry, inbreeding is practiced primarily because it:

Q4. Sonalika and Kalyan Sona are well-known varieties of which crop?

Q5. Which of the following is NOT a fungal disease?

Q6. Why are meristematic tissues in virus-infected plants often free of the virus?

Q7. The ability of several South Indian states to raise two to three crops of rice annually is mainly due to:

Frequently asked questions

What is the main goal of strategies for enhancement in food production?

The main goal is to increase the availability and quality of food to meet the demands of a growing population through scientific methods in agriculture and animal husbandry.

What is a 'breed' in the context of animal husbandry?

A breed is a group of animals that are related by descent and share similar characteristics like appearance, size, and features.

Why is inbreeding practiced in animal husbandry?

Inbreeding is practiced to increase homozygosity, which helps in accumulating desirable genes and eliminating undesirable recessive genes, leading to the development of pure lines.

What is the significance of early-yielding rice varieties?

Early-yielding rice varieties allow farmers to cultivate multiple crops (2-3) in a single year from the same land, significantly increasing overall rice production.

How does meristem culture help in obtaining virus-free plants?

Meristematic tissues divide rapidly, and this faster rate of cell division compared to viral multiplication prevents the virus from infecting the meristem, allowing for the regeneration of healthy, virus-free plants.

Are all plant diseases caused by fungi?

No, plant diseases can be caused by various pathogens, including fungi, bacteria, viruses, and other microorganisms. For example, black rot of crucifers is a bacterial disease.

Important links

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