Major Aspects of Somatic Hybridization

Introduction

Somatic hybridization is a recent innovation in plant breeding that overcomes these limitations. Somatic hybridization is the fusion of two somatic cells from different plant species to produce a hybrid. In this process, the two parent plants are not crossed sexually; instead, their somatic cells are fused in vitro to produce a hybrid plant.

Somatic hybridization is a powerful tool in plant breeding because it can be used to combine desirable traits from different plant species that are not sexually compatible. Below we shall explore the major aspects of somatic hybridization, including its history, mechanisms, applications, advantages, and limitations.

Plant breeding is an age-old practice that has been undertaken by humans to obtain better yield, quality, and resistance to biotic and abiotic stresses. Plant hybridization, the process of crossing two genetically different plants to obtain a hybrid, has been the primary method used for plant breeding.

However, conventional hybridization techniques have certain limitations, such as limited genetic variability, incompatibility barriers, and long breeding cycles.

History of Somatic Hybridization

The history of somatic hybridization dates back to the early 1900s when Haberlandt first proposed the idea of fusing plant cells to create new hybrids. However, it was not until the 1960s that the first somatic hybrids were produced by fusing cells of Nicotiana glauca and N. lagomorphic.

Since then, somatic hybridization has been extensively studied and developed in various plant species.

Mechanisms of Somatic Hybridization

Somatic hybridization involves the fusion of two somatic cells from different plant species. The somatic cells are isolated from the parent plants and cultured in vitro.

Once the cells have divided and formed a callus, they are treated with chemicals or subjected to an electric field to promote cell fusion. The resulting hybrid cells are then cultured to form a new plant.

There are two main mechanisms of somatic hybridization −

• Protoplast Fusion: Protoplast fusion involves the isolation of protoplasts, which are plant cells that have had their cell walls removed. The protoplasts from the two parent plants are then fused using chemicals or enzymes.

• Electrofusion Electrofusion involves the use of an electric field to fuse the two somatic cells.

Applications of Somatic Hybridization

Somatic hybridization has many applications in plant breeding. One of the main applications is the production of hybrid plants that have desirable traits from both parent plants.

For example, somatic hybridization can be used to combine the resistance to diseases of one plant species with the high yield of another plant species. Somatic hybrids can also be used to produce plants with improved stress tolerance, such as resistance to drought or salinity.

Hybrid of Wheat

Another application of somatic hybridization is the production of plants with novel traits that are not found in either parent plant. This is because somatic hybridization can create new combinations of genes that are not found in the parent plants. For example, somatic hybrids can be used to produce plants with altered flower colors, improved fragrance, or modified growth habits.

Advantages of Somatic Hybridization

Somatic hybridization has several advantages over traditional plant breeding techniques.

• One of the main advantages is that it can overcome incompatibility barriers between plant species. In traditional plant breeding, it is often difficult to cross plants from different species due to genetic incompatibilities. However, somatic hybridization can bypass these barriers by fusing the somatic cells of the parent plants.

• Another advantage of somatic hybridization is that it can create plants with a high degree of genetic variability. This is because somatic hybridization can produce new combinations of genes that are not found in the parent plants. As a result, somatic hybrids can have traits that are not present in either parent, making them valuable in plant breeding programs.

• Somatic hybridization also has a shorter breeding cycle compared to traditional plant breeding techniques. Conventional plant breeding can take several years to produce a new hybrid, whereas somatic hybridization can produce a new hybrid within a few months. This is because somatic hybridization can be done in vitro and does not require the lengthy process of growing plants to maturity.

Limitations of Somatic Hybridization

Despite its many advantages, somatic hybridization also has limitations that need to be addressed. One of the main limitations is that the process of somatic fusion is not always successful. Somatic fusion can result in the death of the hybrid cells, or the hybrid cells may not develop into a viable plant.

This can be due to a variety of factors, such as genetic incompatibilities, the use of incompatible chemicals, or inefficient fusion techniques.

Another limitation of somatic hybridization is that the resulting hybrids can have an unstable genome. This is because somatic hybridization can produce new combinations of genes that are not found in the parent plants. As a result, the hybrids may exhibit unpredictable traits or genetic instability, which can make them unsuitable for commercial production.

Finally, somatic hybridization is a relatively expensive and time-consuming process. The process requires specialized equipment and expertise, making it difficult for smaller plant breeding programs to adopt somatic hybridization.

Additionally, the cost of producing somatic hybrids can be higher compared to traditional plant breeding methods.

Conclusion

Somatic hybridization is a powerful tool in plant breeding that offers many advantages over traditional plant breeding techniques. The ability to combine desirable traits from different plant species and overcome incompatibility barriers makes somatic hybridization a valuable tool in plant breeding programs.

However, somatic hybridization also has limitations that need to be addressed, such as the high cost and time required for the process, as well as the potential for unstable genomes in the resulting hybrids.

As technology continues to improve, somatic hybridization will likely become more accessible and cost-effective, making it an increasingly important tool in plant breeding for the development of new crops with desirable traits.