Breeding Methods for Self-Pollinated Crops I (Pure Line, Mass Selection)

Question No. 1 Marks +1 -0 Time

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Which of the following statements best defines a Pure Line in the context of plant breeding for self-pollinated crops?

A. A population derived from multiple self-pollinated plants that are phenotypically similar.
B. A progeny of a single self-pollinated homozygous plant.
C. A group of plants selected for specific traits from a cross-pollinated population.
D. A collection of plants that are genetically identical due to vegetative propagation.

Question No. 2 Marks +1 -0 Time

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Mass selection in self-pollinated crops primarily aims to improve the population by:

A. Increasing the homozygosity of individual plants rapidly.
B. Shifting the frequency of desirable genes in a heterogeneous population.
C. Creating new genetic combinations through controlled crosses.
D. Producing genetically identical clones of superior plants.

Question No. 3 Marks +1 -0 Time

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Consider the following characteristics:

1. High degree of genetic uniformity.
2. Requires progeny testing for confirmation of genetic worth.
3. Relatively quick and inexpensive to implement.
4. Effective for improving landraces with considerable phenotypic variation.

Which of these characteristics are primarily associated with Pure Line Selection?

A. 1 and 2 only
B. 2 and 3 only
C. 1, 2 and 4 only
D. 3 and 4 only

Question No. 4 Marks +1 -0 Time

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Which of the following is a major disadvantage of Pure Line Selection compared to Mass Selection in self-pollinated crops?

A. It is less effective in maintaining genetic purity.
B. It often leads to a narrower genetic base in the developed variety.
C. It cannot be used for improving quantitative traits.
D. It requires less time and fewer resources.

Question No. 5 Marks +1 -0 Time

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Johannsen's classic experiment with Princess beans demonstrated the principle of pure lines. What was his key finding?

A. Selection within a pure line is highly effective in increasing yield.
B. Environmental factors have no influence on phenotypic variation within a pure line.
C. Selection within a pure line is ineffective because the genetic variation is exhausted.
D. Cross-pollination is essential for maintaining genetic diversity in pure lines.

Question No. 6 Marks +1 -0 Time

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In Mass Selection for self-pollinated crops, why is the absence of progeny testing a significant limitation?

A. It makes the selection process too expensive and time-consuming.
B. It prevents the identification of desirable recessive alleles.
C. It increases the risk of selecting phenotypically superior plants that are not genetically superior.
D. It leads to complete loss of genetic variability in the population.

Question No. 7 Marks +1 -0 Time

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Which of the following scenarios is Mass Selection most suitable for in self-pollinated crops?

A. Developing a new variety with extremely high genetic uniformity for a niche market.
B. Improving a highly inbred population that has reached its genetic potential.
C. The initial improvement of a heterogeneous landrace with observable phenotypic variation.
D. Breeding for resistance to a newly emerged, highly virulent pathogen.

Question No. 8 Marks +1 -0 Time

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What is the genetic consequence of continuous self-pollination in a heterozygous plant over several generations?

A. An increase in heterozygosity by 50% per generation.
B. A decrease in heterozygosity by 50% per generation, leading to homozygosity.
C. No change in the proportion of homozygous and heterozygous genotypes.
D. Random fluctuations in heterozygosity, depending on environmental factors.

Question No. 9 Marks +1 -0 Time

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Match the following breeding methods with their primary characteristics:

Method	Characteristic
1. Pure Line Selection	P. Simple and less time-consuming
2. Mass Selection	Q. Results in genetically uniform varieties
	R. Progeny testing is essential
	S. Retains more genetic variability

A. 1-Q,R; 2-P,S
B. 1-P,S; 2-Q,R
C. 1-Q,S; 2-P,R
D. 1-P,R; 2-Q,S

Question No. 10 Marks +1 -0 Time

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Why is Pure Line Selection generally not effective for improving cross-pollinated crops?

A. Cross-pollinated crops naturally have high levels of homozygosity.
B. Inbreeding depression occurs rapidly, reducing vigor and fertility.
C. They are resistant to self-pollination, making pure line development impossible.
D. Genetic variability is too low to make meaningful selections.

Question No. 11 Marks +1 -0 Time

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A breeder wants to improve the yield of a local self-pollinated wheat variety that has been maintained by farmers for generations. The variety shows significant variation in plant height, tillering, and grain size. Which breeding method would be a practical and effective initial step?

A. Hybridization followed by single seed descent.
B. Backcross breeding to incorporate a specific gene.
C. Mass selection from the existing heterogeneous population.
D. Mutation breeding to induce new desirable traits.

Question No. 12 Marks +1 -0 Time

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Which of the following is an advantage of Mass Selection over Pure Line Selection in self-pollinated crops?

A. Produces varieties with greater genetic uniformity.
B. More effective in eliminating undesirable recessive alleles.
C. Maintains a broader genetic base, enhancing adaptability.
D. Allows for precise control over individual plant genetic makeup.

Question No. 13 Marks +1 -0 Time

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Consider the following statements regarding the application of breeding methods:

1. Pure line selection is ideal for improving highly uniform, established varieties.
2. Mass selection is well-suited for improving populations with a narrow genetic base.
3. Both methods rely heavily on the principle of self-pollination in the selected crop.

How many of the above statements are correct?

A. None
B. One
C. Two
D. Three

Question No. 14 Marks +1 -0 Time

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What role did Wilhelm Johannsen play in the development of plant breeding theory?

A. He discovered the principles of Mendelian inheritance.
B. He coined the terms 'gene', 'genotype', and 'phenotype', and demonstrated the limits of selection within pure lines.
C. He developed the first hybrid corn varieties.
D. He proposed the theory of evolution by natural selection.

Question No. 15 Marks +1 -0 Time

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Which of the following describes the genetic status of a variety developed through Pure Line Selection?

A. Heterozygous and heterogeneous
B. Homozygous and homogeneous
C. Heterozygous and homogeneous
D. Homozygous and heterogeneous

Question No. 16 Marks +1 -0 Time

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Which factor is most likely to confound the effectiveness of Mass Selection in a highly variable environment?

A. High heritability of the selected trait.
B. The ability to accurately identify genetically superior plants based on phenotype alone.
C. Lack of genetic variation within the initial population.
D. The presence of significant genotype-by-environment interaction.

Question No. 17 Marks +1 -0 Time

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What is the primary reason for performing progeny tests in Pure Line Selection?

A. To increase genetic diversity within the selected line.
B. To ensure that selected plants are cross-pollinated.
C. To confirm the genetic purity and heritability of desirable traits.
D. To introduce new mutations into the breeding program.

Question No. 18 Marks +1 -0 Time

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Which of the following pairs correctly describes a characteristic of Mass Selection?

A. Genetic Basis: Derived from a single homozygous plant; Selection Unit: Individual plant progeny.
B. Genetic Basis: Shifts gene frequency in a heterogeneous population; Selection Unit: Phenotypically superior individuals.
C. Genetic Basis: Aims for complete homozygosity; Selection Unit: Clonal propagation.
D. Genetic Basis: Introduces new alleles through mutation; Selection Unit: Lines with improved yield.

Question No. 19 Marks +1 -0 Time

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A breeder has a population of a self-pollinated crop that is known to contain a mixture of different genotypes. She wants to rapidly obtain a more uniform and higher-yielding variety. Which of the following sequences of steps would be most appropriate using Pure Line Selection?

A. Bulk harvest from superior plants → Field plot testing → Release as new variety.
B. Select individual superior plants → Harvest seeds separately → Grow progeny rows → Select best progeny rows → Replicate testing → Release.
C. Hybridize with a wild relative → Self-pollinate for several generations → Select best F5 plants.
D. Irradiate seeds with gamma rays → Select for desired mutations → Stabilize lines.

Question No. 20 Marks +1 -0 Time

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The term 'landrace' in the context of crop breeding most closely refers to:

A. A modern, genetically uniform commercial variety.
B. A wild relative of a cultivated crop species.
C. A heterogeneous, locally adapted traditional variety developed through farmer selection.
D. A genetically modified crop grown in specific regions.

Question No. 21 Marks +1 -0 Time

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Which of the following statements about the effectiveness of selection is FALSE?

A. Selection is ineffective in a pure line because there is no genetic variation to act upon.
B. Mass selection is more effective in heterogeneous populations than in homogeneous ones.
C. The effectiveness of selection is directly proportional to the heritability of the trait.
D. Selection can create new genetic variation in a population.

Question No. 22 Marks +1 -0 Time

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Identify the correct statement regarding the historical development of breeding methods for self-pollinated crops.

A. Pure line selection predates mass selection as a recognized scientific method.
B. Mass selection was the primary method used by ancient farmers before the understanding of genetics.
C. Johannsen's work on pure lines disproved the concept of Mendelian inheritance.
D. The discovery of DNA structure led directly to the development of pure line breeding.

Question No. 23 Marks +1 -0 Time

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What is the main reason that Mass Selection is considered a 'less precise' method compared to Pure Line Selection?

A. It requires more advanced genetic markers.
B. It does not involve the bulking of seeds.
C. It does not separate environmental effects from genetic effects as effectively.
D. It is primarily used for cross-pollinated crops.

Question No. 24 Marks +1 -0 Time

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Which of the following is a common objective for both Pure Line Selection and Mass Selection in self-pollinated crops?

A. To introduce genes from wild relatives.
B. To create hybrid vigor.
C. To improve the overall performance of the crop variety.
D. To develop disease resistance through genetic engineering.

Question No. 25 Marks +1 -0 Time

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A plant breeder is working with a local variety of barley (a self-pollinated crop) that is known to be a mixture of several distinct genotypes. The breeder wants to isolate the best genotype to create a highly uniform and stable variety. Which method is most appropriate for this goal?

A. Recurrent selection
B. Clonal selection
C. Pure line selection
D. Synthetic variety development

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