Plant Breeding & Genetics MCQs March 21, 2025December 31, 2024 by u930973931_answers 15 Score: 0 Attempted: 0/15 Subscribe 1. Which of the following is the most likely outcome of a cross between two heterozygous plants for a single gene (Aa × Aa)? (A) 100% dominant phenotype (B) 25% recessive phenotype, 75% dominant phenotype (C) 50% dominant phenotype, 50% recessive phenotype (D) 75% dominant phenotype, 25% recessive phenotype 2. Which of the following techniques is used to introduce a specific gene into a plant genome? (A) Hybridization (B) Polyploidy induction (C) Genetic transformation (D) Backcrossing 3. What is the primary goal of backcrossing in plant breeding? (A) To increase the genetic diversity of a population (B) To introduce a specific trait from one variety into another while maintaining the original genotype (C) To generate F1 hybrids for commercial production (D) To produce genetically uniform offspring 4. What does “self-incompatibility” in plants refer to? (A) The ability of plants to self-pollinate effectively (B) The inability of plants to produce pollen (C) The mechanism that prevents self-fertilization to promote genetic diversity (D) The ability of plants to produce offspring without pollination 5. Which of the following statements best describes the concept of “homozygous” in genetics? (A) An individual with two different alleles for a gene (B) An individual with two identical alleles for a gene (C) An individual with no alleles for a gene (D) An individual that expresses a dominant allele 6. In polyploidy, what is the primary genetic consequence when a tetraploid (4n) crosses with a diploid (2n)? (A) The offspring will be triploid (3n), which is usually sterile. (B) The offspring will be tetraploid (4n). (C) The offspring will be diploid (2n) and fertile. (D) The offspring will be pentaploid (5n), with high fertility. 7. What is the purpose of “marker-assisted selection” (MAS) in plant breeding? (A) To identify plants that carry desirable traits using molecular markers (B) To increase genetic diversity through controlled hybridization (C) To induce genetic mutations that promote beneficial traits (D) To ensure that only homozygous plants are selected for breeding 8. Which of the following is a key characteristic of quantitative traits in plant genetics? (A) They are controlled by a single gene and exhibit Mendelian inheritance patterns. (B) They are controlled by multiple genes and show continuous variation. (C) They can be easily influenced by environmental factors, but not by genetic factors. (D) They are always recessive and express only in homozygous conditions. 9. What is “genomic selection” in plant breeding? (A) The selection of plants based on their phenotype alone (B) The selection of plants based on genomic data to predict breeding values (C) The process of selecting plants for hybridization (D) The selection of plants based on visual markers or traits 10. What is the primary goal of “mutation breeding” in plant breeding? (A) To produce hybrids with enhanced vigor and yield potential (B) To create new genetic variation by inducing random mutations (C) To ensure that only homozygous plants are used for breeding (D) To cross two genetically identical plants to maintain uniformity 11. In a Mendelian dihybrid cross (AaBb × AaBb), what is the expected phenotypic ratio in the F2 generation? (A) 9:3:3:1 (B) 1:1:1:1 (C) 3:1 (D) 1:2:1 12. Which of the following breeding methods is most commonly used to create new crop varieties with high disease resistance? (A) Mass selection (B) Backcross breeding (C) Hybridization (D) Pure line selection 13. What is “inbreeding depression” in plant breeding? (A) The increase in vigor and fertility due to close inbreeding (B) The reduction in genetic diversity due to self-pollination (C) The reduction in plant vigor and fertility due to continued inbreeding (D) The enhancement of desirable traits through inbreeding 14. Which of the following methods is best suited for increasing the seed set in apomictic plants (plants that reproduce asexually through seeds)? (A) Cross-pollination (B) Self-pollination (C) Inducing polyploidy (D) Tissue culture 15. Which of the following is an example of “heterosis” (hybrid vigor) in plant breeding? (A) F1 hybrids outperform both parent plants in yield and disease resistance. (B) Crossbreeding leads to genetic uniformity in the progeny. (C) Offspring exhibit a mix of traits from both parent plants but do not show superior performance. (D) The F2 generation is genetically more diverse than the F1 generation.