TRB PG Assistant - Plant Breeding - methods of crop improvement: introduction, selection, heterosis, hybridization, polyploidy, mutation breeding Online Test (MCQ Quiz)

1. Which method of crop improvement involves introducing desirable genes from one variety into another through controlled pollination?

A) Hybridization B) Selection C) Mutation Breeding D) Polyploidy

2. The process of selecting individual plants with superior traits from a mixed population for further propagation is known as:

A) Introduction B) Hybridization C) Selection D) Heterosis

3. 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?

A) Polyploidy B) Mutation Breeding C) Heterosis D) Introduction

4. The deliberate alteration of the genetic makeup of a plant using physical or chemical agents to induce mutations is called:

A) Hybridization B) Polyploidy C) Introduction D) Mutation Breeding

5. An increase in the number of chromosome sets in an organism, often leading to larger size and vigor, is termed as:

A) Heterosis B) Polyploidy C) Selection D) Hybridization

6. Which method involves bringing a variety or species from a different region or country to a new area for cultivation?

A) Introduction B) Selection C) Heterosis D) Mutation Breeding

7. What is the primary goal of selection in plant breeding?

A) To create new genetic combinations B) To increase chromosome number C) To isolate and propagate superior genotypes D) To induce random genetic changes

8. In heterosis, the superior performance of the F1 hybrid is often attributed to:

A) Dominance B) Epistasis C) Overdominance and/or epistasis D) Recessive gene action

9. Which type of hybridization involves crossing between plants of the same species but different varieties?

A) Intervarietal hybridization B) Interspecific hybridization C) Intergeneric hybridization D) Backcrossing

10. A plant with three sets of chromosomes (3n) is an example of:

A) Monoploid B) Diploid C) Triploid D) Tetraploid

11. Which mutagen is commonly used to induce point mutations in plants?

A) Gamma rays B) Ethyleneimine (EI) C) X-rays D) Ultraviolet radiation

12. The introduction of a pre-existing improved variety into a new region without any genetic modification is called:

A) Acclimatization B) Introduction C) Naturalization D) Adaptation

13. Mass selection is a type of selection where:

A) Individual plants are selected based on phenotype B) A large population is selected based on a common desirable trait C) Selection is based on performance of progenies D) Selection is done in multiple generations

14. What is 'hybrid breakdown' in the context of heterosis?

A) The loss of heterotic effect in subsequent generations (F2 onwards) B) The failure of the hybrid to germinate C) The reduced fertility of the F1 hybrid D) The increased susceptibility of the hybrid to diseases

15. Crossing between plants of different species within the same genus is known as:

A) Intervarietal hybridization B) Interspecific hybridization C) Intergeneric hybridization D) Intraspecific hybridization

16. Autopolyploidy refers to polyploidy arising from:

A) The fusion of gametes from different species B) The doubling of the chromosome set within the same species C) The addition of chromosomes from a different genus D) The loss of a chromosome set

17. Which of the following is a major advantage of mutation breeding?

A) It can create new gene combinations not possible through hybridization. B) It always results in increased yield. C) It is a very rapid method for crop improvement. D) It requires less genetic diversity.

18. What is a 'check variety' used for in crop improvement?

A) To induce mutations B) To compare the performance of new varieties C) To maintain genetic purity D) To measure heterosis

19. Which type of selection is based on the performance of the progeny of individual plants?

A) Mass selection B) Pure-line selection C) Progeny selection D) Family selection

20. The phenomenon where the F1 hybrid is less vigorous than its parents is called:

A) Heterosis B) Hybrid vigor C) Negative heterosis or anti-heterosis D) Overdominance

21. Backcrossing is a technique used to:

A) Introduce a single gene into an otherwise elite genetic background B) Combine multiple desirable traits from different parents C) Induce polyploidy D) Increase genetic diversity rapidly

22. An organism with four sets of chromosomes (4n) is called:

A) Diploid B) Triploid C) Tetraploid D) Hexaploid

23. Which of the following is an example of a physical mutagen?

A) Ethyl methanesulfonate (EMS) B) Colchicine C) Gamma rays D) Nitrous acid

24. What is the primary challenge in the 'Introduction' method of crop improvement?

A) Low genetic variability B) Adaptation to new environmental conditions and potential pest/disease introduction C) Difficulty in controlling pollination D) High cost of inducing mutations

25. Recurrent selection is a method primarily used for:

A) Developing pure lines B) Increasing homozygosity C) Improving quantitative traits by accumulating favorable alleles D) Creating polyploids

26. The term 'hybrid vigor' is synonymous with:

A) Inbreeding depression B) Apomixis C) Heterosis D) Polyploidy

27. What is the main advantage of using mutation breeding for creating new varieties?

A) It is a highly predictable method. B) It can create new alleles and genetic variation. C) It always results in superior hybrids. D) It is faster than hybridization.

28. Which polyploid has 6 sets of chromosomes (6n)?

A) Diploid B) Tetraploid C) Hexaploid D) Octoploid

29. The process of crossing plants from different genera is called:

A) Interspecific hybridization B) Intervarietal hybridization C) Intergeneric hybridization D) Intrageneric hybridization

30. What is the term for a variety that is introduced from another country and grown successfully in a new environment?

A) Native variety B) Exotic variety C) Indigenous variety D) Hybrid variety

31. Which selection method involves selecting individual plants based on their own performance, assuming a relatively uniform population?

A) Progeny selection B) Mass selection C) Pedigree selection D) Recurrent selection

32. The phenomenon where inbred lines, when crossed, produce offspring with superior traits is the basis of:

A) Polyploidy breeding B) Mutation breeding C) Hybridization for heterosis breeding D) Introduction

33. What is the primary challenge in interspecific or intergeneric hybridization?

A) High probability of success B) Lack of genetic variation C) Cross-incompatibility and reduced fertility of hybrids D) Rapid development of stable varieties

34. Allopolyploidy results from:

A) Chromosome doubling within a species B) The fusion of gametes from different species followed by chromosome doubling C) The spontaneous mutation of chromosomes D) The loss of chromosomes

35. Which chemical is commonly used to induce polyploidy by inhibiting spindle formation during mitosis?

A) Ethyleneimine B) Colchicine C) EMS D) Gamma rays

36. The process of selecting desirable genotypes from a segregating population and maintaining records of their ancestry is known as:

A) Mass selection B) Pedigree selection C) Pure-line selection D) Bulk selection

37. What is the main objective of developing hybrid varieties?

A) To achieve uniformity in the offspring B) To exploit heterosis for increased yield and vigor C) To increase chromosome number D) To introduce genes from wild relatives

38. Which of the following is a disadvantage of polyploidy breeding?

A) Often leads to larger plant size B) Can result in reduced fertility in odd-numbered polyploids (e.g., triploids) C) Increases genetic diversity D) Can be used to overcome interspecific hybridization barriers

39. A plant breeding method that directly uses induced or spontaneous genetic changes is:

A) Hybridization B) Selection C) Mutation Breeding D) Introduction

40. The selection of individual plants that are genetically uniform and breed true is called:

A) Mass selection B) Progeny selection C) Pure-line selection D) Recurrent selection

41. What is the genetic basis of heterosis?

A) Complete dominance of desirable alleles in homozygous state B) Overdominance (heterozygote superiority) and/or epistasis C) Accumulation of recessive deleterious alleles D) Increased homozygosity

42. Which type of hybridization is essential for creating new species or overcoming reproductive isolation barriers between species?

A) Intervarietal hybridization B) Interspecific hybridization C) Intergeneric hybridization D) Intraspecific hybridization

43. A plant with an even number of chromosome sets, such as 4n or 6n, generally has:

A) Lower fertility B) Higher fertility compared to odd-numbered polyploids C) No viable seeds D) Reduced vigor

44. Which method is useful for transferring a specific desirable gene from a wild relative into an elite cultivated variety?

A) Mutation Breeding B) Polyploidy C) Backcrossing D) Mass Selection

45. The introduction of a variety developed in one agro-climatic zone into another agro-climatic zone is termed:

A) Introduction B) Acclimatization C) Naturalization D) Adaptation

46. What is the main goal of using selection in plant breeding programs?

A) To create genetic mutations B) To increase the ploidy level C) To isolate and propagate individuals with desirable traits D) To induce heterosis

47. Which of the following is a key characteristic of heterosis?

A) Increased homozygosity B) Superior performance of F1 hybrids over parents C) Reduced genetic variation D) Sterility of offspring

48. The process of inducing mutations using agents like gamma rays or EMS is part of:

A) Hybridization B) Selection C) Mutation Breeding D) Introduction

49. Which of the following is an example of an allopolyploid?

A) A plant with 4 sets of chromosomes from the same species B) A plant with 6 sets of chromosomes from the same species C) Triticale (a hybrid of wheat and rye) D) A plant with 3 sets of chromosomes from the same species

Plant Breeding - methods of crop improvement: introduction, selection, heterosis, hybridization, polyploidy, mutation breeding - Online Test

Test Results