1. Which of the following breeding methods is most effective for improving self-pollinated crops like wheat?
a) Pedigree method
b) Mass selection
c) Hybridization
d) Heterosis breeding
Answer: a) Pedigree method
Explanation: The pedigree method is most effective for self-pollinated crops like wheat, where inbreeding depression is minimized, and genetic improvement is achieved through successive selection of superior individuals over generations.
2. In hybridization breeding, the F1 generation is produced by crossing:
a) Two homozygous parents of the same species
b) Two genetically identical parents
c) Two genetically different individuals of different species
d) Two genetically different individuals of the same species
Answer: d) Two genetically different individuals of the same species
Explanation: In hybridization breeding, the F1 generation is produced by crossing two genetically different individuals of the same species, typically involving different varieties or lines.
3. What is the primary objective of “backcross breeding” in field crops?
a) To improve disease resistance
b) To increase the yield potential
c) To incorporate a single desirable trait from a donor parent into an elite variety
d) To increase genetic diversity within a crop
Answer: c) To incorporate a single desirable trait from a donor parent into an elite variety
Explanation: Backcross breeding is used to transfer a specific desirable trait (like disease resistance or drought tolerance) from a donor parent to an elite variety, while retaining the genetic background of the elite variety.
4. Which of the following is the primary advantage of using molecular markers in crop breeding?
a) Increased genetic diversity
b) Direct selection of desirable traits without needing to phenotype
c) Faster seed production
d) Lower cost of breeding programs
Answer: b) Direct selection of desirable traits without needing to phenotype
Explanation: Molecular markers allow breeders to directly select for desirable traits at the DNA level, without the need to wait for phenotypic expression, speeding up the breeding process.
5. In field crop breeding, “heterosis” refers to:
a) The ability of hybrids to outperform both parental lines in terms of yield or other traits
b) The genetic purity of inbred lines
c) The decrease in plant vigor due to genetic incompatibility
d) The introduction of foreign genes into a crop species
Answer: a) The ability of hybrids to outperform both parental lines in terms of yield or other traits
Explanation: Heterosis, or hybrid vigor, refers to the phenomenon where the F1 hybrid generation outperforms both parental lines in traits like yield, disease resistance, and overall vigor due to genetic diversity.
6. Which of the following is NOT a characteristic typically selected for in field crop breeding programs?
a) High yield potential
b) Resistance to pests and diseases
c) Dwarf stature for easier harvesting
d) High seed dormancy for long storage
Answer: d) High seed dormancy for long storage
Explanation: High seed dormancy is not typically desired in field crop breeding, as it can delay germination and reduce crop establishment. Breeding usually focuses on traits like high yield, pest resistance, and easy harvesting.
7. Which of the following is the primary goal of breeding for “genetic diversity” in field crops?
a) To create uniformity in crop populations for industrial farming
b) To enhance resistance to diseases and environmental stresses
c) To reduce the overall number of different crop varieties
d) To improve the visual appeal of crops
Answer: b) To enhance resistance to diseases and environmental stresses
Explanation: Increasing genetic diversity in field crops is important to improve resilience against diseases, pests, and varying environmental conditions, which can help ensure sustainable production over time.
8. In the context of field crop breeding, “MAS” stands for:
a) Marker-assisted selection
b) Molecular agricultural systems
c) Modified agronomy techniques
d) Mass agricultural selection
Answer: a) Marker-assisted selection
Explanation: Marker-assisted selection (MAS) is a technique that uses molecular markers to select for specific genes or traits of interest, allowing for faster and more precise breeding without the need for phenotypic observation.
9. The “three-line system” of hybrid seed production in field crops involves the use of:
a) Two inbred lines and a third line used for crossing
b) One parental line and two hybrid lines
c) Two hybrid lines and a third line for cross-pollination
d) A female sterile line, a maintainer line, and a restorer line
Answer: d) A female sterile line, a maintainer line, and a restorer line
Explanation: The three-line system of hybrid seed production involves three types of lines: a female sterile line (which does not produce viable pollen), a maintainer line (to maintain the sterility), and a restorer line (which restores fertility when crossed with the sterile line).
10. Which of the following methods is most commonly used to develop hybrid varieties of maize?
a) Pedigree method
b) Mass selection
c) Topcross breeding
d) Inbreeding and cross-pollination
Answer: d) Inbreeding and cross-pollination
Explanation: In maize breeding, hybrid varieties are typically developed by inbreeding to create inbred lines and then crossing these lines to produce hybrids. This method is used to exploit heterosis for higher yields.
11. Which of the following is an example of a quantitative trait in field crops?
a) Plant height
b) Flower color
c) Resistance to a specific disease
d) Seed shape
Answer: a) Plant height
Explanation: Quantitative traits, like plant height, are controlled by multiple genes and exhibit continuous variation, making them more challenging to breed for than qualitative traits, which are typically controlled by single genes.
12. In field crop breeding, “progeny testing” is primarily used to:
a) Identify desirable traits in the parent plants
b) Test the viability of seeds in different environments
c) Evaluate the genetic potential of offspring by assessing their traits
d) Introduce foreign genes into crop plants
Answer: c) Evaluate the genetic potential of offspring by assessing their traits
Explanation: Progeny testing is used to evaluate the genetic potential of parent plants by analyzing the performance of their offspring, which helps in selecting superior plants for breeding.
13. Which of the following is the most commonly used breeding method for developing varieties of self-pollinated crops like rice?
a) Mass selection
b) Pedigree selection
c) Hybridization
d) Backcross breeding
Answer: b) Pedigree selection
Explanation: Pedigree selection is the most commonly used method for self-pollinated crops like rice. It allows for the gradual improvement of varieties through the selection of superior plants over multiple generations.
14. In hybrid seed production, the “male sterile” line is essential for:
a) Producing pollen to fertilize the female parent
b) Ensuring that the hybrid seeds do not self-pollinate
c) Enhancing genetic diversity
d) Increasing the yield potential of the hybrid
Answer: b) Ensuring that the hybrid seeds do not self-pollinate
Explanation: The male sterile line is crucial for hybrid seed production because it prevents self-pollination by making the plant unable to produce functional pollen, ensuring that the hybridization process produces only cross-pollinated seeds.
15. Which of the following is a disadvantage of using inbreeding to develop pure lines in field crop breeding?
a) Increased heterosis
b) Reduced genetic variability and potential in the population
c) Increased disease resistance
d) Greater crop yield stability
Answer: b) Reduced genetic variability and potential in the population
Explanation: Inbreeding leads to reduced genetic variability, which can increase the risk of inbreeding depression, where the expression of harmful recessive traits becomes more prominent, limiting the population’s potential.