Breeding and hybrid production — Which breeding method uses enzymatic/chemical removal of cell walls and fusion of protoplasts from two sexually incompatible plant species?

Introduction / Context:
Protoplast fusion enables somatic hybridization between distantly related plants that cannot cross sexually. By removing cell walls, plasma membranes can be brought into close contact and fused to combine nuclear and cytoplasmic genomes.

Given Data / Assumptions:

• Cell walls are removed using cellulases/pectinases.
• Fusion is induced by polyethylene glycol (PEG) and/or electric fields (electrofusion).
• Somatic hybrids and cybrids can be regenerated via tissue culture.

Concept / Approach:
The key distinction is wall removal plus fusion, which is unique to protoplast fusion. Mass selection and marker-assisted selection do not involve cell wall removal; transformation introduces DNA but does not fuse whole cells.

Step-by-Step Solution:

Verification / Alternative check:
Hybrid cells can be confirmed by cytological markers, selectable markers, or organelle DNA profiling.

Why Other Options Are Wrong:

Common Pitfalls:
Losing viability due to osmotic shock; careful stabilization and plating density are critical.

Final Answer:
Protoplast fusion.