🌿 Concept:-Apomixis, Parthenocarpy, and Polyembryony 🌿
1. Apomixis refers to:
a) Fertilization without pollination
b) Seed formation without fertilization
c) Asexual reproduction through spores
d) Formation of gametes without meiosis
Answer: b
Explanation: Apomixis is a form of asexual reproduction in plants where seeds are produced without fertilization.
2. Which of the following plants exhibits apomixis?
a) Mango
b) Citrus
c) Dandelion
d) Maize
Answer: c
Explanation: Dandelion shows apomixis, forming seeds without fertilization.
3. Agamospermy is another term for:
a) Polyembryony
b) Apomixis
c) Parthenocarpy
d) Cross-pollination
Answer: b
Explanation: Agamospermy literally means seed formation without sexual fusion, synonymous with apomixis.
4. In apomixis, the embryo is formed from:
a) Fertilized zygote
b) Somatic cells of ovule
c) Pollen grain
d) Endosperm
Answer: b
Explanation: The embryo arises from somatic cells like nucellus or integuments in apomixis.
5. Which of the following is true about apomixis?
a) Genetic variation is increased
b) Offspring are genetically identical to parent
c) Involves meiosis
d) Requires pollination
Answer: b
Explanation: Apomictic reproduction produces clonal offspring identical to the parent.
6. Apomixis is beneficial in agriculture because it:
a) Reduces yield
b) Maintains hybrid vigour
c) Causes mutations
d) Prevents seed formation
Answer: b
Explanation: Hybrids retain their superior traits due to apomixis, useful in crop improvement.
7. The type of apomixis where embryo develops from nucellar cells:
a) Sporophytic apomixis
b) Gametophytic apomixis
c) Vegetative propagation
d) Parthenocarpy
Answer: a
Explanation: In sporophytic apomixis, embryo develops directly from somatic cells of ovule.
8. Gametophytic apomixis involves:
a) Formation of unreduced embryo sac
b) Pollination
c) Formation of male gametes
d) Fertilization
Answer: a
Explanation: Here, unreduced embryo sacs form and give rise to embryos without fertilization.
9. Which of the following is not an example of apomixis?
a) Mango
b) Dandelion
c) Citrus
d) Allium
Answer: a
Explanation: Mango shows normal sexual reproduction, not apomixis.
10. Which statement is correct regarding apomixis?
a) Endosperm never forms
b) Fertilization is essential
c) Embryo forms without gamete fusion
d) Only occurs in gymnosperms
Answer: c
Explanation: Apomixis bypasses gamete fusion for embryo formation.
11. Apomictic seed is always:
a) Diploid
b) Haploid
c) Polyploid
d) Triploid
Answer: a
Explanation: Somatic cells are diploid, so apomictic embryos are diploid.
12. Which of these plants shows facultative apomixis?
a) Citrus
b) Dandelion
c) Mango
d) Maize
Answer: a
Explanation: Facultative apomixis occurs when plants can reproduce sexually or asexually; citrus is an example.
13. Apomixis does not occur in which plant part?
a) Nucellus
b) Integuments
c) Embryo sac
d) Pollen grain
Answer: d
Explanation: Apomixis is ovule-based, not pollen-based.
14. Advantages of apomixis include:
a) Genetic variation
b) Uniformity of crops
c) Requirement of pollinators
d) Slower reproduction
Answer: b
Explanation: Apomixis ensures uniform offspring, useful in agriculture.
15. Apomixis is a form of:
a) Sexual reproduction
b) Vegetative propagation
c) Asexual reproduction
d) Cross-pollination
Answer: c
Explanation: It is asexual as fertilization is bypassed.
16. Parthenocarpy is the development of:
a) Fruit without fertilization
b) Seed without fruit
c) Seed without fertilization
d) Fruit after pollination
Answer: a
Explanation: Parthenocarpy leads to fruit formation without fertilization; seeds may be absent.
17. Which fruit is an example of parthenocarpy?
a) Mango
b) Banana
c) Tomato
d) Citrus
Answer: b
Explanation: Banana is naturally seedless due to parthenocarpy.
18. Artificial parthenocarpy is induced by:
a) Hormones
b) Cross-pollination
c) Insects
d) Self-pollination
Answer: a
Explanation: Plant hormones like auxins and gibberellins induce artificial parthenocarpy.
19. Natural parthenocarpy occurs in:
a) Papaya
b) Mango
c) Orange
d) Dandelion
Answer: a
Explanation: Papaya shows natural parthenocarpy in some varieties.
20. Seedless grapes are formed due to:
a) Apomixis
b) Polyembryony
c) Parthenocarpy
d) Cross-pollination
Answer: c
Explanation: Hormonal or natural parthenocarpy leads to seedless grapes.
21. Parthenocarpic fruits are beneficial because:
a) Reduce fruit size
b) Increase fruit number
c) Avoid seed formation
d) Both b and c
Answer: d
Explanation: Parthenocarpic fruits are seedless and often higher in quality and quantity.
22. Which hormone is most commonly used for artificial parthenocarpy?
a) Cytokinin
b) Gibberellin
c) ABA
d) Ethylene
Answer: b
Explanation: Gibberellins stimulate fruit development without fertilization.
23. Parthenocarpic fruits can also develop through:
a) Pollination only
b) Pollination-independent fruit set
c) Seed formation
d) Cross-fertilization
Answer: b
Explanation: Pollination-independent fruit set is characteristic of parthenocarpy.
24. Which of these is a genetically modified parthenocarpic fruit?
a) Tomato
b) Apple
c) Mango
d) Papaya
Answer: a
Explanation: Some tomato varieties have been engineered for parthenocarpy to produce seedless fruits.
25. Parthenocarpy ensures:
a) Seed dispersal
b) Uniformity in crops
c) Fertilization
d) Genetic variability
Answer: b
Explanation: Seedless fruits ensure uniform quality and faster production.
26. Which term is synonymous with seedless fruit formation?
a) Apomixis
b) Polyembryony
c) Parthenocarpy
d) Vegetative propagation
Answer: c
Explanation: Parthenocarpy directly leads to seedless fruits.
27. In parthenocarpy, the ovary develops into fruit without:
a) Hormones
b) Fertilization
c) Cell division
d) Water
Answer: b
Explanation: Fertilization is not required for parthenocarpic fruit development.
28. Banana is an example of:
a) Polyembryony
b) Apomixis
c) Parthenocarpy
d) Sexual reproduction
Answer: c
Explanation: Bananas are seedless and develop via parthenocarpy.
29. Advantages of parthenocarpic fruits include:
a) Easy harvesting
b) Better taste
c) Seedless nature
d) All of the above
Answer: d
Explanation: Seedless fruits like banana are easier to eat and harvest, improving market value.
30. Which is not an example of parthenocarpy?
a) Banana
b) Tomato
c) Grapes
d) Mango
Answer: d
Explanation: Mangoes develop seeds via normal fertilization, not parthenocarpy.
31. Polyembryony is the formation of:
a) Multiple seeds per fruit
b) Multiple embryos in a single seed
c) Seedless fruit
d) Haploid embryos
Answer: b
Explanation: Polyembryony is when more than one embryo develops in a single seed.
32. An example of polyembryony is:
a) Citrus
b) Mango
c) Banana
d) Tomato
Answer: a
Explanation: Citrus seeds often contain multiple embryos, some from nucellar tissue.
33. Polyembryony occurs due to:
a) Fertilization only
b) Development from somatic cells and fertilized zygote
c) Only parthenogenesis
d) Cross-pollination
Answer: b
Explanation: Both zygotic and somatic (nucellar) embryos can develop in polyembryony.
34. Advantage of polyembryony in agriculture:
a) Clonal propagation
b) Increased fruit size
c) Reduced flowering
d) Seedless fruits
Answer: a
Explanation: Nucellar embryos are clones of the mother, ensuring uniform crops.
35. In citrus, extra embryos are formed from:
a) Zygotic cells only
b) Nucellus
c) Pollen
d) Ovary wall
Answer: b
Explanation: Nucellar cells give rise to extra embryos in citrus seeds.
36. Polyembryony can result in:
a) Only one viable seedling
b) Multiple seedlings from a single seed
c) Seedless fruits
d) Haploid plants
Answer: b
Explanation: Each embryo can give rise to a seedling, sometimes leading to several plants from one seed.
37. Which of the following shows polyembryony?
a) Mango
b) Citrus
c) Banana
d) Papaya
Answer: b
Explanation: Citrus commonly exhibits polyembryony.
38. Nucellar embryony is a type of:
a) Apomixis
b) Polyembryony
c) Parthenocarpy
d) Sexual reproduction
Answer: b
Explanation: Nucellar embryos contribute to polyembryony and are clones of the mother.
39. Polyembryony helps in:
a) Rapid vegetative propagation
b) Genetic variability
c) Seedless fruit formation
d) Reducing pollination
Answer: a
Explanation: Multiple embryos can be used for clonal propagation of superior plants.
40. Zygotic embryos in polyembryony are:
a) Haploid
b) Diploid and sexually formed
c) Clones of mother
d) Seedless
Answer: b
Explanation: Zygotic embryos result from fertilization and are genetically distinct.
41. The embryos in polyembryony may originate from:
a) Only gametes
b) Only somatic cells
c) Both gametes and somatic cells
d) Only pollen
Answer: c
Explanation: Polyembryony can involve zygotic (gamete) and nucellar (somatic) embryos.
42. Which of the following is NOT true about polyembryony?
a) Multiple embryos in one seed
b) All embryos are genetically identical
c) Some embryos are clones, some are zygotic
d) Useful in citrus propagation
Answer: b
Explanation: Only nucellar embryos are identical; zygotic embryos are genetically distinct.
43. In polyembryony, the term “nucellar seedlings” refers to:
a) Zygotic embryos
b) Embryos from nucellus
c) Seedless fruits
d) Haploid seedlings
Answer: b
Explanation: Nucellar embryos develop from maternal tissue and are clonal.
44. Polyembryony can be used to:
a) Obtain genetically identical plants
b) Increase fruit size
c) Induce seedlessness
d) Reduce vegetative propagation
Answer: a
Explanation: Nucellar seedlings are used to propagate true-to-type plants.
45. Polyembryony is most common in:
a) Gymnosperms
b) Citrus
c) Banana
d) Tomato
Answer: b
Explanation: Citrus shows both zygotic and nucellar embryos.
46. In polyembryony, if all embryos grow, it may lead to:
a) One strong plant
b) Competition among seedlings
c) Seedless fruits
d) Male sterility
Answer: b
Explanation: Multiple seedlings in a seed can compete for resources.
47. Which process is common in both apomixis and polyembryony?
a) Fertilization
b) Development from somatic cells
c) Seedlessness
d) Pollination
Answer: b
Explanation: Both can involve embryos from somatic cells without fertilization.
48. Polyembryony differs from apomixis because:
a) Only one embryo forms
b) Polyembryony may have both zygotic and somatic embryos
c) Apomixis produces multiple embryos
d) Polyembryony is seedless
Answer: b
Explanation: Polyembryony can have both zygotic and nucellar embryos, unlike apomixis which is fully asexual.
49. Citrus polyembryony is exploited for:
a) Producing hybrids
b) Producing clonal rootstocks
c) Seedless fruits
d) Pollination
Answer: b
Explanation: Nucellar seedlings provide uniform rootstocks for citrus grafting.
50. Which of the following sequences is correct in special modes?
a) Apomixis → Parthenocarpy → Polyembryony
b) Polyembryony → Apomixis → Parthenocarpy
c) Parthenocarpy → Polyembryony → Apomixis
d) Apomixis → Polyembryony → Parthenocarpy
Answer: a
Explanation: Apomixis (seed without fertilization), Parthenocarpy (fruit without seed), Polyembryony (multiple embryos per seed).
