Key Fact
Apomixis & polyembryony
Apomixis: seed without fertilisation (asexual seed). Polyembryony: multiple embryos in one seed (Citrus, mango). Used to fix hybrid vigour for several generations.
-- NCERT Class 12 Biology, Ch. 1, p. 23Apomixis Polyembryony
8 MCQs9-step worked example
Source: NCERT ReproductionOfficial key: NTA-verifiedLast updated: 26 Sep 2026
Apomixis Polyembryony, explained for NEET
The trap: NEET often tests whether you can distinguish apomixis from vegetative propagation, and whether you know polyembryony produces multiple embryos within a single seed — not multiple seeds.
Apomixis is seed production without fertilisation. The embryo develops from the maternal tissue, so the offspring is a genetic clone of the mother plant. NCERT Class 12 Biology Chapter 1 (page 22) notes that some species like Citrus and grasses in Asteraceae employ apomixis. There are two main mechanisms:
- Diplospory — the megaspore mother cell skips meiosis (or undergoes restitution) and directly develops into the embryo sac. No reduction division → diploid egg → embryo without fertilisation.
- Apospory — a nucellar cell (somatic, 2n) develops into an embryo sac, bypassing the megaspore mother cell entirely.
In both cases, the endosperm may still require pollination (pseudogamy) — the central cell fuses with a sperm for endosperm development, but the egg cell develops parthenogenetically. This is a common NEET confusion: apomixis does NOT always mean pollination is absent; it means fertilisation of the egg is absent.
Polyembryony is the occurrence of more than one embryo inside a single seed. In Citrus, adventive embryos arise from nucellar cells alongside the sexually-formed zygotic embryo. The result: one seed germinates into multiple seedlings, most of which are maternal clones (nucellar embryos) while one may be the hybrid zygotic embryo.
Why NEET cares: Apomixis is commercially valuable — it can fix hybrid vigour across generations without segregation. If a hybrid variety could reproduce by apomixis, farmers would not need to buy fresh hybrid seeds every season. This application angle appears in assertion-reason and application-type questions.
Can you answer these Apomixis Polyembryony MCQs?
Select an option to see the explanation. Wrong answers show why your choice was tempting — and name the exact trap it exploits.
MCQ 1Easy RecallPractice
Apomixis is best defined as:
Show answer and why every option is right or wrong
Answer: A. Apomixis is seed production without fertilisation of the egg cell. The embryo develops from maternal tissue. NCERT Class 12 Biology Chapter 1, page 22.
Why B is wrong: B is wrong because fertilisation is precisely what is ABSENT in apomixis. Pollination may still occur (pseudogamy for endosperm) but egg fertilisation does not.
Why C is wrong: C is wrong because vegetative propagation does not involve seed formation at all — apomixis specifically produces seeds.
Why D is wrong: D is wrong because parthenocarpy is fruit development without fertilisation (seedless fruits), not seed development without fertilisation.
MCQ 2Easy RecallPractice
In apospory, the embryo sac develops from:
Show answer and why every option is right or wrong
Answer: B. Apospory involves a nucellar cell (2n, somatic) developing directly into an embryo sac, bypassing the megaspore mother cell entirely. Apospory goes beyond NCERT: NCERT Class 12 Biology Chapter 1, page 22 defines apomixis without naming its types.
Why A is wrong: A is wrong because normal meiosis of the megaspore mother cell is the sexual pathway — apospory bypasses this cell completely.
Why C is wrong: C is wrong because integumentary cells form the seed coat, not the embryo sac in apospory.
Why D is wrong: D is wrong because synergids are part of the mature embryo sac — they do not give rise to a new embryo sac.
MCQ 3Easy RecallPractice
Polyembryony in Citrus results from:
Show answer and why every option is right or wrong
Answer: C. In Citrus, nucellar cells (somatic, 2n) around the embryo sac divide to form adventive embryos alongside the zygotic embryo, all within one seed. NCERT Class 12 Biology Chapter 1, page 23.
Why A is wrong: A is wrong because each ovule has only one egg cell; multiple pollen tubes do not create multiple embryos within one seed.
Why B is wrong: B is wrong because cleavage polyembryony (zygote splitting) occurs in some species but is NOT the mechanism in Citrus — here it is adventive (nucellar) embryony.
Why D is wrong: D is wrong because megaspore fusion does not occur; normally only one functional megaspore survives in monosporic development.
MCQ 4Direct ApplicationPractice
A farmer wants to maintain hybrid vigour across generations without purchasing new seeds each year. Which reproductive strategy, if introduced into the crop, would achieve this?
Show answer and why every option is right or wrong
Answer: C. Apomixis produces seeds with embryos that are genetic clones of the mother plant — hybrid vigour is preserved without segregation. This eliminates the need for annual hybrid seed purchase. NCERT Class 12 Biology Chapter 1, page 23.
Why A is wrong: A is wrong because self-pollination of a hybrid (heterozygous) plant causes segregation in the F2 generation, LOSING hybrid vigour.
Why B is wrong: B is wrong because crossing with wild-type introduces new alleles and disrupts the specific heterozygous combination that confers hybrid vigour.
Why D is wrong: D is wrong because parthenocarpy produces seedless fruits — it does not address seed reproduction or maintaining genotype across generations.
MCQ 5Direct ApplicationPractice
In pseudogamy, pollination is required even though the egg develops without fertilisation. The role of pollination here is to:
Show answer and why every option is right or wrong
Answer: A. In pseudogamy, the egg develops parthenogenetically (no sperm fusion), but endosperm formation requires fertilisation of the central cell (or at minimum, pollination stimulus). Without endosperm, the seed cannot nourish the developing embryo. Pseudogamy goes beyond NCERT, which covers apomixis in NCERT Class 12 Biology Chapter 1, page 22.
Why B is wrong: B is wrong because in pseudogamy the egg develops autonomously without any fertilisation trigger — it is the central cell that needs the sperm.
Why C is wrong: C is wrong because the defining feature of apomixis is that the embryo is entirely maternal — no male genetic contribution to the embryo occurs.
Why D is wrong: D is wrong because fruit ripening is not the function served by pseudogamous pollination; the function is endosperm nutrition for the embryo.
MCQ 6Direct ApplicationPractice
A seed of Citrus is germinated and produces five seedlings. Four are phenotypically identical to the mother plant and one shows variation. The most likely explanation is:
Show answer and why every option is right or wrong
Answer: B. In Citrus polyembryony, adventive embryos from nucellar cells are maternal clones (identical to mother), while the single zygotic embryo carries recombined genes and may show variation. NCERT Class 12 Biology Chapter 1, page 23.
Why A is wrong: A is wrong because zygotic cleavage would produce genetically identical embryos (all from one zygote) — it would not explain the ONE variant seedling.
Why C is wrong: C is wrong because each ovule has only one egg cell; multiple pollen donors cannot produce five embryos within a single seed through fertilisation.
Why D is wrong: D is wrong because each ovule contains only one megaspore mother cell, not five — and even so, only one functional megaspore typically survives.
MCQ 7Concept TrapPractice
Which of the following correctly distinguishes apomixis from vegetative propagation?
Show answer and why every option is right or wrong
Answer: D. The key distinction: apomixis produces seeds (albeit without egg fertilisation), while vegetative propagation bypasses the entire seed-formation process and uses vegetative parts (runners, tubers, bulbs). Vegetative propagation is not in this chapter; NCERT Class 12 Biology Chapter 1, page 22 covers apomixis.
Why A is wrong: A is wrong because BOTH produce genetically uniform (clonal) offspring — neither generates diversity (unlike sexual reproduction).
Why B is wrong: B is wrong because apomixis specifically AVOIDS normal meiosis (diplospory) or bypasses the megaspore mother cell entirely (apospory) — meiosis is not required.
Why C is wrong: C is wrong because vegetative propagation, by definition, does NOT involve seed formation — it uses stems, roots, or leaves.
MCQ 8Concept TrapPractice
An assertion-reason question:
Assertion (A): Apomixis is of great agricultural significance for hybrid seed production.
Reason (R): Apomictic seeds preserve the exact parental genotype without segregation.
Show answer and why every option is right or wrong
Answer: A. A is true — apomixis can fix hybrid vigour commercially. R is true — apomictic embryos are maternal clones, so no segregation occurs. R directly explains WHY apomixis has agricultural significance: hybrid genotype is preserved indefinitely. NCERT Class 12 Biology Chapter 1, page 23.
Why B is wrong: B is wrong because R IS the correct explanation — the agricultural value of apomixis specifically derives from the fact that it prevents segregation of the hybrid genotype.
Why C is wrong: C is wrong because R is factually true — apomictic seeds do preserve the parental genotype without meiotic segregation.
Why D is wrong: D is wrong because A is factually true — apomixis IS agriculturally significant for maintaining hybrid vigour across generations.
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How do you solve a Apomixis Polyembryony question? A worked example
- 1
Given
A mango variety shows the following: seeds produce multiple seedlings; most seedlings are genetically identical to the parent tree; one seedling per seed occasionally differs.
- 2
Required
Identify: (a) the phenomenon, (b) the origin of the identical seedlings, (c) the origin of the variant seedling.
- 3
Concept
Polyembryony — multiple embryos within a single seed. In many angiosperms (notably Citrus, mango), nucellar cells develop into adventive embryos (2n, maternal clones) alongside the sexually-produced zygotic embryo.
- 4
Key principle
Nucellar embryos = somatic origin = clone of mother. Zygotic embryo = product of fertilisation = genetic recombination possible.
- 5
Application
• Multiple seedlings from one seed → polyembryony confirmed.• Most identical to parent → these are nucellar (adventive) embryos.• One variant → this is the zygotic embryo (sexual fusion introduced new allele combinations).
- 6
Reasoning
No formula needed. The reasoning is purely conceptual: adventive embryony from nucellar cells is mitotic (no meiosis, no recombination) → clones. The zygotic embryo underwent meiosis + fertilisation → potential variation.
- 7
Final answer
(a) Polyembryony. (b) Identical seedlings arise from adventive (nucellar) embryos — maternal clones. (c) The variant seedling is the zygotic embryo formed by sexual fertilisation.
- 8
Common trap
Confusing polyembryony with "multiple seeds per fruit." Polyembryony is multiple embryos within ONE seed. A fruit with many seeds (e.g., tomato) is NOT polyembryony.
- 9
Similar NEET-style question
"In Citrus, if a seed produces 4 seedlings of which 3 are identical to the mother plant, the
3 identical seedlings most likely developed from: (a) synergids (b) antipodal cells (c) nucellar cells (d) zygote cleavage" — Answer: (c) nucellar cells.
What to remember before solving Apomixis Polyembryony questions
More in Reproduction: 10 exam traps and mistakes · 1 question pattern from its other lessons.
Apomixis Polyembryony questions from past NEET papers
No question in our NEET 2020–2025 set targets this topic directly.
Sources
Page numbers are the ones printed in the current NCERT textbook (2023 rationalised edition), unless marked pre-2023. The books are free at ncert.nic.in.
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