Somatic hybridization is the process of breeding new plants by fusing isolated somatic protoplasts taken from various body parts/vegetative tissues of plants except for reproductive cells.

Somatic hybridization Steps

1. Fusion of Protoplast

The protoplast is a cell devoid of a cell wall. The fusion of protoplasts can be achieved by three methods:

• Mechanical fusion: fusion is done mechanically through placing the protoplasts on a depression slide.
• Spontaneous fusion: enzymatic breakdown and lytic mechanisms of cell walls.
• Induced fusion: fusion aided by using chemicals called fusogens like NaNO3, polyethylene glycol, etc.

1. Selection of Hybrid Cells

Not all the protoplasts fuse, some leftover protoplasts fuse to develop a heterokaryon.

There are three methods for the selection:

• Biochemical method: Biochemical compounds are employed to select the fused cell out of the total cells which are unfused. There are two methods:
  • Drug sensitivity
  • Auxotrophic mutants
• Visual method: Cells grown on various media are separated visually. 
• Cytometric method: In this method flow cytometry and fluorescent cells are used for easy selection of cells.

1. Identification of Hybrid Plant

There is a need to use some molecular genotyping to determine the hybrid plants that resulted from the development. 

• Morphology: In  this technique hybrids bear some characteristics of both the plants easily recognizable.
• Isoenzyme analysis: Isoenzymes are different forms of the same enzymes which can catalyze a different reaction.

Symmetric and asymmetric: When the chromosome numbers are present corresponding to the parents.