Protoplast fusion technology has been utilized
in many crops to generate allotetraploid somatic hybrids,
and sometimes autotetraploids as a byproduct of the process.
A brief history of this technology development is
provided, along with a simple protocol developed for citrus,
which can be easily adapted to other plants. Protoplast
fusion has become a significant tool in ploidy manipulation
that can be applied in various cultivar improvement
schemes.