Apomixis and Polyembryony Questions in English

(A) Apomixis is a form of asexual reproduction that mimics sexual reproduction.
In haploid apogamy (or haploid apomixis),the embryo develops from a haploid cell of the embryo sac other than the egg cell,such as the synergids or antipodal cells,without fertilization.
Option $A$ describes this process correctly.
Option $B$ refers to haploid parthenogenesis,where the embryo develops from the egg cell.
Option $C$ refers to adventive embryony,where the embryo develops from diploid nucellar cells.

(C) Apomixis is a form of asexual reproduction that mimics sexual reproduction. It is a mechanism to produce seeds without fertilization. Therefore,option $C$ is incorrect because it states that apomixis is a form of sexual reproduction,whereas it is actually a form of asexual reproduction.

(C) Apomixis is a form of asexual reproduction that mimics sexual reproduction,where seeds are produced without fertilization.
In hybrid crops,the main problem is that the desirable traits segregate in the next generation,meaning farmers must buy new hybrid seeds every year.
If an apomictic gene is introduced into these hybrids,the seeds produced will be clones of the parent plant.
Consequently,there will be no segregation of characters,and farmers can harvest and reuse these seeds for subsequent plantings without losing the hybrid vigor or desired traits.

(D) Apomixis is a form of asexual reproduction that mimics sexual reproduction. In apomixis,seeds are produced without fertilization. Since there is no fusion of gametes (meiosis and syngamy are bypassed),the embryo formed is genetically identical to the parent plant. Therefore,the ploidy of the apomictic embryo will be the same as the mother plant ($2n$ in most cases,but it depends on the ploidy of the parent). Thus,the embryo is $2n$ or identical to the mother plant.

(B) Polyembryony is the occurrence of more than one embryo in a seed.
$i$. It increases the chances of survival of new plants by providing multiple embryos.
$ii$. Nucellar polyembryony is useful in horticulture as it produces virus-free plants.
$iii$. The formation of seedless fruits is known as parthenocarpy,which is a different biological process,not a significance of polyembryony.
$iv$. Cleavage polyembryony results in genetically identical embryos.
Therefore,statement $iii$ is not a significance of polyembryony.

(D) Apomixis is a form of asexual reproduction that mimics sexual reproduction. In this process,seeds are formed without the occurrence of fertilization (syngamy) and meiosis. Since it produces seeds without fertilization,it is considered a mimicry of sexual reproduction.

(B) The correct matches are as follows:
$i$. Diplospory: In this type,the embryo sac develops from the megaspore mother cell without meiosis. Example: $Taraxacum$.
$ii$. Apospory: In this type,the embryo sac develops from a somatic cell of the nucellus. Example: $Hieracium$ or $Mango$ (in some contexts).
$iii$. Adventive polyembryony: Embryos develop directly from diploid sporophytic cells like nucellus or integuments. Example: $Citrus$ and $Mango$.
$iv$. Non-recurrent apomixis: The embryo sac is haploid and the embryo develops from the egg cell without fertilization. Example: $Nicotiana$.
Therefore,the correct matching is $i-c, ii-a, iii-d, iv-b$.

(A) Statement $I$ is correct: Apogamy refers to the development of an embryo from a gametophytic cell (like synergids or antipodal cells) without fertilization.
Statement $II$ is correct: Apospory is the development of a gametophyte directly from a diploid sporophytic cell (like nucellar cells) without the process of meiosis,resulting in a diploid gametophyte.
Since both statements are scientifically accurate descriptions of these apomictic processes,the correct answer is that both statements are correct.

(A) The phenomenon where embryos develop directly from diploid cells of the nucellus is known as adventive polyembryony.
In this process,the diploid cells of the nucellus surrounding the embryo sac start dividing and protrude into the embryo sac to develop into embryos.
This is commonly observed in species like $Citrus$ and $Mangifera$ (mango).
Therefore,the correct option is $A$.

(C) In $Taraxacum$,the process of apomixis occurs,specifically a type of agamospermy called diplospory.
In this process,the embryo sac develops directly from the diploid megaspore mother cell $(MMC)$ without undergoing meiosis.
Since the $MMC$ is diploid $(2n)$,the resulting embryo sac is also diploid (unreduced).
This allows the plant to produce seeds without fertilization.

(A) Polyembryony is the occurrence of more than one embryo in a seed.
It was first discovered by Antonie van Leeuwenhoek in $1719$ in the seeds of $Citrus$ (orange/lemon).
In $Citrus$,it is a common phenomenon where multiple embryos develop from the nucellus or integuments,leading to the formation of several embryos within a single seed.

(A) Apomixis is a form of asexual reproduction that mimics sexual reproduction,where seeds are formed without the process of fertilization (syngamy) and meiosis.
In the family $Asteraceae$ and some grasses,$Apomixis$ is a common phenomenon.
$Parthenocarpy$ refers to the development of fruit without fertilization.
$Amphimixis$ is the normal sexual reproduction involving the fusion of gametes.
$Vivipary$ is the germination of seeds while still attached to the parent plant.
Therefore,the correct option is $A$.

(D) Statement-$X$ is correct: Apomixis is indeed observed in families like $Asteraceae$ and grasses.
Statement-$Y$ is correct: Apomixis is a specialized form of asexual reproduction that produces seeds without fertilization,effectively mimicking sexual reproduction.
Statement-$Z$ is correct: In many apomictic species,the embryo sac develops from a diploid megaspore mother cell without undergoing meiosis (reduction division),leading to the formation of a diploid egg cell.
Therefore,all three statements are correct.

(B) - Production of Apomictic seeds.
Apomixis is a form of asexual reproduction that mimics sexual reproduction. In this process,seeds are produced without fertilization. This significantly reduces the cost of hybrid seed production,allowing plant breeders to develop new varieties more quickly and at a lower cost,which benefits farmers by eliminating the need to purchase new hybrid seeds every year.

(D) The correct answer is $D$ (apomixis).
Apomixis is a form of asexual reproduction that mimics sexual reproduction.
In this process,seeds are produced without the fusion of male and female gametes (fertilisation).
Therefore,seeds formed through apomixis are genetically identical to the parent plant.