Plant Breeding - methods of crop improvement: introduction, selection, heterosis, hybridization, polyploidy, mutation breeding - One Line Questions

1. Which of the following is an example of an allopolyploid? — Triticale (a hybrid of wheat and rye)
2. The introduction of a pre-existing improved variety into a new region without any genetic modification is called: — Introduction
3. Allopolyploidy results from: — The fusion of gametes from different species followed by chromosome doubling
4. What is the genetic basis of heterosis? — Overdominance (heterozygote superiority) and/or epistasis
5. Recurrent selection is a method primarily used for: — Improving quantitative traits by accumulating favorable alleles
6. An organism with four sets of chromosomes (4n) is called: — Tetraploid
7. Which polyploid has 6 sets of chromosomes (6n)? — Hexaploid
8. In heterosis, the superior performance of the F1 hybrid is often attributed to: — Overdominance and/or epistasis
9. Which of the following is an example of a physical mutagen? — Gamma rays
10. Which chemical is commonly used to induce polyploidy by inhibiting spindle formation during mitosis? — Colchicine
11. Which mutagen is commonly used to induce point mutations in plants? —
12. An increase in the number of chromosome sets in an organism, often leading to larger size and vigor, is termed as: — Polyploidy
13. The phenomenon where the F1 hybrid is less vigorous than its parents is called: — Negative heterosis or anti-heterosis
14. What is the primary challenge in interspecific or intergeneric hybridization? — Cross-incompatibility and reduced fertility of hybrids
15. Which method of crop improvement involves introducing desirable genes from one variety into another through controlled pollination? — Hybridization
16. The deliberate alteration of the genetic makeup of a plant using physical or chemical agents to induce mutations is called: — Mutation Breeding
17. A plant breeding method that directly uses induced or spontaneous genetic changes is: — Mutation Breeding
18. The process of inducing mutations using agents like gamma rays or EMS is part of: — Mutation Breeding
19. The term 'hybrid vigor' is synonymous with: — Heterosis
20. Which of the following is a key characteristic of heterosis? — Superior performance of F1 hybrids over parents
21. Mass selection is a type of selection where: — A large population is selected based on a common desirable trait
22. The process of crossing plants from different genera is called: — Intergeneric hybridization
23. Which type of hybridization involves crossing between plants of the same species but different varieties? — Intervarietal hybridization
24. Crossing between plants of different species within the same genus is known as: — Interspecific hybridization
25. Which type of hybridization is essential for creating new species or overcoming reproductive isolation barriers between species? — Interspecific hybridization
26. Backcrossing is a technique used to: — Introduce a single gene into an otherwise elite genetic background
27. The process of selecting individual plants with superior traits from a mixed population for further propagation is known as: — Selection
28. Which method involves bringing a variety or species from a different region or country to a new area for cultivation? — Introduction
29. The introduction of a variety developed in one agro-climatic zone into another agro-climatic zone is termed: — Introduction
30. Which of the following is a major advantage of mutation breeding? — It can create new gene combinations not possible through hybridization.
31. What is the main advantage of using mutation breeding for creating new varieties? — It can create new alleles and genetic variation.
32. What is the primary challenge in the 'Introduction' method of crop improvement? — Adaptation to new environmental conditions and potential pest/disease introduction
33. A plant with an even number of chromosome sets, such as 4n or 6n, generally has: — Higher fertility compared to odd-numbered polyploids
34. Which type of selection is based on the performance of the progeny of individual plants? — Progeny selection
35. The process of selecting desirable genotypes from a segregating population and maintaining records of their ancestry is known as: — Pedigree selection
36. The selection of individual plants that are genetically uniform and breed true is called: — Pure-line selection
37. A plant with three sets of chromosomes (3n) is an example of: — Triploid
38. Which method is useful for transferring a specific desirable gene from a wild relative into an elite cultivated variety? — Backcrossing
39. What is the term for a variety that is introduced from another country and grown successfully in a new environment? — Exotic variety
40. Which of the following is a disadvantage of polyploidy breeding? — Can result in reduced fertility in odd-numbered polyploids (e.g., triploids)
41. What is the phenomenon where the F1 generation of a cross between two genetically dissimilar parents shows significantly enhanced vigor and yield compared to either parent? — Heterosis
42. The phenomenon where inbred lines, when crossed, produce offspring with superior traits is the basis of: — Hybridization for heterosis breeding
43. Which selection method involves selecting individual plants based on their own performance, assuming a relatively uniform population? — Mass selection
44. Autopolyploidy refers to polyploidy arising from: — The doubling of the chromosome set within the same species
45. What is 'hybrid breakdown' in the context of heterosis? — The loss of heterotic effect in subsequent generations (F2 onwards)
46. What is the main objective of developing hybrid varieties? — To exploit heterosis for increased yield and vigor
47. What is the main goal of using selection in plant breeding programs? — To isolate and propagate individuals with desirable traits
48. What is the primary goal of selection in plant breeding? — To isolate and propagate superior genotypes
49. What is a 'check variety' used for in crop improvement? — To compare the performance of new varieties
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