1. Which of the following is a primary focus in maize breeding for increasing yield potential?
a) Shortening the plant height
b) Enhancing pest resistance
c) Increasing kernel number and size
d) Reducing flowering time
Answer: c) Increasing kernel number and size
Explanation: One of the main objectives in maize breeding is to increase kernel number and size, which directly impacts the grain yield. This is often achieved through improving the genetic potential for higher seed set and kernel size.
2. In maize, the “three-way cross” hybrid is a cross between which of the following?
a) Two inbred lines
b) A single hybrid and an inbred line
c) Two open-pollinated varieties
d) Three inbred lines
Answer: d) Three inbred lines
Explanation: A three-way cross hybrid is the result of crossing two inbred lines to form a hybrid, and then crossing that hybrid with a third inbred line. This method aims to combine the strengths of multiple lines for improved performance.
3. Which of the following is a significant challenge in the breeding of drought-tolerant maize?
a) Increased susceptibility to pests
b) Low seed germination under stress
c) Limited genetic variability for drought resistance
d) Reduced grain quality under water stress
Answer: c) Limited genetic variability for drought resistance
Explanation: Drought tolerance is a complex trait that requires specific genetic variability for effective breeding. The challenge is the limited genetic pool for this trait in maize, making breeding for drought tolerance more difficult.
4. Which of the following is a commonly used technique to improve the nutritional quality of maize in breeding programs?
a) Hybridization
b) Mutation breeding
c) Biofortification
d) Clonal selection
Answer: c) Biofortification
Explanation: Biofortification is the process of increasing the nutritional content of maize, such as increasing levels of pro-vitamin A (carotenoids), zinc, and iron, through conventional breeding or genetic modification to improve human nutrition.
5. In millet breeding, which of the following traits is a priority for improving tolerance to heat stress?
a) Increased leaf area
b) Higher root biomass
c) Early flowering
d) Shorter plant height
Answer: b) Higher root biomass
Explanation: Increasing root biomass in millet can enhance drought and heat stress tolerance. A well-developed root system helps the plant access moisture deeper in the soil, which is crucial under high-temperature stress conditions.
6. Which of the following is a key reason for the low adoption of hybrid maize in certain parts of the world?
a) High cost of hybrid seed
b) Lower yields compared to open-pollinated varieties
c) Poor pest resistance
d) Limited genetic diversity in hybrids
Answer: a) High cost of hybrid seed
Explanation: The high cost of hybrid seed is a significant barrier to its adoption, especially in resource-poor settings, where farmers may not afford the high initial investment required for hybrid maize.
7. In the breeding of pearl millet, which of the following is a commonly used technique for improving disease resistance?
a) Genetic modification
b) Marker-assisted selection
c) Hybridization
d) Radiation-induced mutagenesis
Answer: b) Marker-assisted selection
Explanation: Marker-assisted selection (MAS) is often used to identify and select for disease-resistant traits in pearl millet breeding, particularly for resistance to downy mildew and blast diseases.
8. Which of the following is a characteristic of “QPM” (Quality Protein Maize)?
a) Increased fiber content
b) Higher levels of essential amino acids like lysine and tryptophan
c) Improved drought tolerance
d) Increased seed size
Answer: b) Higher levels of essential amino acids like lysine and tryptophan
Explanation: Quality Protein Maize (QPM) is a variety of maize with enhanced protein quality, particularly increased levels of essential amino acids such as lysine and tryptophan, making it more nutritionally beneficial for humans and animals.
9. Which of the following genetic tools is used in maize breeding to enhance resistance to the European corn borer?
a) Genetic modification using Bt genes
b) Crossbreeding with wild relatives
c) Marker-assisted selection for pest resistance genes
d) Use of polyploidy to enhance resistance
Answer: a) Genetic modification using Bt genes
Explanation: Bt (Bacillus thuringiensis) genes are used in genetically modified maize to provide resistance against pests like the European corn borer. These genes produce proteins that are toxic to specific insect larvae.
10. In millet breeding, what is a primary objective for increasing the yield of sorghum and pearl millet?
a) Increasing plant height
b) Reducing flowering time
c) Improving resistance to lodging
d) Enhancing resistance to environmental stresses like drought and heat
Answer: d) Enhancing resistance to environmental stresses like drought and heat
Explanation: Both sorghum and pearl millet are drought and heat-tolerant crops. The primary breeding objective is to improve these traits to ensure stable yield production under stressful environmental conditions.
11. Which of the following breeding methods is primarily used to develop maize hybrids with improved genetic potential for yield?
a) Backcross breeding
b) Self-pollination
c) Cross-pollination between inbred lines
d) Polyploidy induction
Answer: c) Cross-pollination between inbred lines
Explanation: In maize hybrid breeding, cross-pollination between two inbred lines is used to produce hybrids with improved genetic potential for higher yield, as hybrid vigor (heterosis) typically increases performance compared to the inbred parents.
12. Which of the following is a major limitation of using conventional breeding techniques in maize for resistance to biotic stresses?
a) Limited genetic variability in the germplasm
b) Long breeding cycle
c) Lack of molecular markers for disease resistance
d) Increased susceptibility to environmental stresses
Answer: a) Limited genetic variability in the germplasm
Explanation: One of the major limitations in conventional maize breeding for biotic stress resistance is the limited genetic variability in the available germplasm, which can hinder the development of new resistant varieties.
13. Which of the following is a key trait that breeders focus on when developing drought-resistant millet varieties?
a) Larger seed size
b) Increased leaf stomatal conductance
c) Deeper root system
d) Reduced flowering time
Answer: c) Deeper root system
Explanation: A deeper root system is crucial for drought resistance in millet, as it allows the plant to access water from deeper soil layers during periods of water scarcity, ensuring survival and yield stability.
14. What is the main objective of introgressing genes from wild relatives into maize breeding programs?
a) To increase the disease resistance of the maize varieties
b) To enhance the nutritional quality of maize
c) To improve yield by enhancing photosynthesis
d) To increase the genetic diversity and resistance to abiotic stresses
Answer: d) To increase the genetic diversity and resistance to abiotic stresses
Explanation: Wild relatives of maize are often used to introduce new genetic diversity into maize breeding programs, which can improve resistance to abiotic stresses such as drought, heat, and salinity.
15. In the context of maize and millet breeding, what does the term “heterosis” refer to?
a) The ability of plants to survive under low fertility conditions
b) The improved performance of hybrids over their parent lines
c) The transfer of resistance genes from wild species
d) The uniformity of seeds in a hybrid crop
Answer: b) The improved performance of hybrids over their parent lines
Explanation: Heterosis, or hybrid vigor, refers to the phenomenon where hybrid plants outperform their parent lines in traits like yield, growth rate, and stress tolerance due to the combination of superior traits from both parents.