Let’s break down the word apomixis into its two parts, ‘apo’ and mixis,’ where ‘apo’ means away from and’mixis,’ in Greek. Apomixis, as defined by the famous botanist Hans Winker, is the production of seeds without fertilisation. It is referred to as the asexual process because there is no normal sexual reproduction and fertilization does not occur.
Apomixis
The following are key concepts that form the basis of Apomixis.
- Fertilization occurs when the male and female gametes fuse to produce a zygote during sexual reproduction
- The genetic information from two individuals of different types (sexes) is combined during this process
- Apomixis will never result in genetic recombination or population diversity
- Since the offspring produced by apomixis does not experience gene flow, haploid parthenogenesis (the generation of pure lines from a single set of chromosomes) can be used to accomplish rapid development of pure lines
- Apomixis is fairly widespread in higher plants
- Apomictic plants can be found in more than 35 different families
Types of Apomixis
Apomixis is Classified into the following Groups:
- Cell Involved
- Occurrence
- Frequency
Cell Involved
It can be further divided into the types listed below.
Parthenogenesis
Parthenogenesis is the process through which an embryo develops from an egg cell.
Occurrence
Recurrent Apomixis
Also known as gametophyte apomixis, this is a type of apomixis in which both the egg cell and the embryo are diploid, and the embryonic is generated from the megaspore mother cell.
Non-Recurrent Apomixis
Both the egg-cell and the embryo are haploid in non-recurrent apomixis, and the embryo is produced directly from an egg-cell without fertilisation.
Applications
Maintaining Purity
In the case of obligate apomixis, the mother plant’s traits are preserved. This aids in the transmission of the same genotype between generations.
Conservation of Heterosis
There is no segregation in apomixis, hence there is no conservation of heterosis. Hybrid vigour is also preserved by required recurrent apomixis. As a result, heterosis is easily preserved.
Pure Lines Development
Haploid plants are created through haploid apogamy and parthenogenesis, which results in pure lines. After being treated with colchicine, these plants yield pure lines. These assist in increasing yields.
Hybrid Seed Production
Apomixis simplifies the process of creating hybrid seeds. Seeds are created automatically using apomictic techniques without any crossing. The creation of hybrid seed occurs automatically after the development of a hybrid.
Advantages of Apomixis
There are the following Advantages
- Since the genetic structure of apomictic plants is retained, heterozygotic advantages are preserved for many generations. This aids in preserving homozygosity.
- Without segregation, genetically uniform progenies can be created quickly.
- Apomixis also impacts the efficiency with which the maternal features are used in the progenies.
Significance of Apomixis
Apomixis is extremely important in the plant breeding industry since it allows seeds to develop without fertilisation. This process produces cost-effective hybrid seeds that allow for large-scale production in a shorter length of time. This contributes to a higher yield. Furthermore, because apomixis does not require cross-fertilization, it aids in the preservation of the crop plants’ desirable features.
Disadvantages of Apomixis
- Can’t stop harmful genetic mutations from accumulating.
- Usually restricted to specific ecological niches.
- inability to adjust to new surroundings.
Apomixis is the asexual seed generation of apomictic seeds, which are clones of the mother plant. Apomixis is the creation of viable seeds without pollination or fertilisation. These seeds are made from flowers in the same way that conventional seeds are, however, there is no pollen involved. Mangosteen, for example, generates apomictic seeds within the fruit.
Even the dandelion produces a large number of apomictic seeds. Apomixis has the advantage of dramatically lowering the cost of hybrid breeding, allowing plant breeders to develop new seed types more quickly and cheaply. Due to the absence of variation in asexual reproduction, apomictic seeds have the drawback of reducing genetic diversity from parent to offspring plants.
Conclusion
The genetic information from two individuals of different types (sexes) is combined during this process. Apomixis will never result in genetic recombination or population diversity. Since the offspring produced by apomixis does not experience gene flow, haploid parthenogenesis (the generation of pure lines from a single set of chromosomes) can be used to accomplish rapid development of pure lines.
Apomixis is extremely important in the plant breeding industry since it allows seeds to develop without fertilisation. This process produces cost-effective hybrid seeds that allow for large-scale production in a shorter length of time.