Use of apomixis in Plant Breeding
Use of apomixis in Plant Breeding
The Greek terms "APO" (away from) and "mixed" (the process of mixing or mingling) are the roots of the word "apomixis." It describes how a plant grows from a seed without the need for fertilization or typical sexual reproduction. The easiest way to define apomixis is as a reference to the asexual process. The resultant plant is a female parent plant clone.
The female gametophyte, or embryo sac, is created during sexual reproduction by developmental processes that take place inside the ovule. After double fertilization, the resultant components are the embryo and endosperm.
In higher plants, apomixis is a common occurrence. More than 35 groups of plants, including the Gramineae, Rosaceae, Compositae, and Rutaceae, are known to be apomictic. Apomixis is seen in major grains like wheat and maize.
Apomixis Types
There are three commonly known kinds of apomixis: adventitious embryony, apospory, and diplospory.
Diplospory
The megaspore mother cell immediately gives rise to the embryo sac in diplospory, either through mitotic division or by stopping meiosis.
The megaspore mother cell divides mitotically three times to produce eight nuclei during the mitotic diplospory. The embryosac has the same amount of genetic material and chromosomes as before it was decreased.
apospory
The nucellar cells give birth to the apomictic embryo sac during apospory.
In higher plants, this is the most prevalent kind of apomixis.
To create an embryo sac, aposporous starting cells differentiate and proceed through mitosis.
Multiple embryo sacs can occasionally be discovered.
The formation of the sexual embryo sac may be disrupted or displaced, or the apospory embryo sac may begin concurrently with the sexual one.
apospory
The nucellar cells give birth to the apomictic embryo sac during apospory.
In higher plants, this is the most prevalent kind of apomixis.
To create an embryo sac, aposporous starting cells differentiate and proceed through mitosis.
Multiple embryo sacs can occasionally be discovered.
The formation of the sexual embryo sac may be disrupted or displaced, or the apospory embryo sac may begin concurrently with the sexual one.
Unexpected Embryony
This kind of sporophytic apomixis produces embryos straight from the ovule's integument or nucellus.
Through mitotic division, the embryo grows into a structure resembling a bud.
For seeds to be viable, fertilization must occur simultaneously in the adjacent sexual embryo sac. The growing embryos move in its direction in order to get messages and nourishment from the embryo sac.
Apomixis: Recurrent and Non-recurrent
Recurrent apomixis is a process in which the megaspore mother cell develops into the embryo sac, both of which are diploid.
Both the egg cell and the embryo in non-recurrent apomixis are haploid, and the embryo develops from the egg cell directly without fertilization.
Apomixis Vegetative
Rather than flowers, this kind of apomixis produces vegetative bulbils or buds in the inflorescence.
They are easily reproducible and are seen in certain plants like Fragaria, Agave, Poa bulbosa, etc.
This kind of sporophytic apomixis produces embryos straight from the ovule's integument or nucellus.
Through mitotic division, the embryo grows into a structure resembling a bud.
For seeds to be viable, fertilization must occur simultaneously in the adjacent sexual embryo sac. The growing embryos move in its direction in order to get messages and nourishment from the embryo sac.
Apomixis: Recurrent and Non-recurrent
Recurrent apomixis is a process in which the megaspore mother cell develops into the embryo sac, both of which are diploid.
Both the egg cell and the embryo in non-recurrent apomixis are haploid, and the embryo develops from the egg cell directly without fertilization.
Apomixis Vegetative
Rather than flowers, this kind of apomixis produces vegetative bulbils or buds in the inflorescence.
They are easily reproducible and are seen in certain plants like Fragaria, Agave, Poa bulbosa, etc.
What is the mechanism of sporophytic apomixis?
In certain circles, it's also known as sporophytic apomixis. In this sort of apomixis, the ovule may include a megagametophyte. On the other hand, the gametophyte's cells do not give rise to the embryos. The nucellus's cells give rise to them.
In certain circles, it's also known as sporophytic apomixis. In this sort of apomixis, the ovule may include a megagametophyte. On the other hand, the gametophyte's cells do not give rise to the embryos. The nucellus's cells give rise to them.
Benefits of Apomixis
It helps in hybrid seed production.
It is one of the most cost-effective methods to produce seeds.
Apomixis prevents the loss of specific characters in the hybrid.
The reason it matters in the plant breeding sector is that apomixis is a technique that makes seed development possible without the need for fertilizers. This process yields efficient and economical hybrid seeds that enable large-scale manufacturing in a shorter amount of time. This raises the yield in some way.
It helps in hybrid seed production.
It is one of the most cost-effective methods to produce seeds.
Apomixis prevents the loss of specific characters in the hybrid.
The reason it matters in the plant breeding sector is that apomixis is a technique that makes seed development possible without the need for fertilizers. This process yields efficient and economical hybrid seeds that enable large-scale manufacturing in a shorter amount of time. This raises the yield in some way.
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