Question

In somatic cell hybridization,
A. Cell walls of two varieties of a species are removed
B. Fusion of two cells occurs
C. New plantlets are produced
D. All of the above

Answer 1

Hint: Somatic hybridization is a technique that allows the alteration of cellular genomes by protoplast fusion. It contributed to plant breeding in overcoming common crossing barriers among different plant species and changes in genetics and breeding. This method was implemented in order to overcome the drawbacks of the sexual hybridization method.

Complete answer:
• The fusion of protoplasts- It involves the mixing of protoplasts of two different genomes and can be achieved by spontaneous, mechanical, or induced fusion methods.

• Selection of hybrid cells- After this fusion process, the protoplast consists of a heterogeneous mixture (un-fused chloroplasts, homokaryons, and heterokaryons). It is therefore necessary to select the hybrid cells that are called heterokaryons. The commonly used methods employed are biochemical, visual, and cytometric methods.

• Identification of hybrid cells- A clear proof of genetic contribution from both the parental protoplasts is required for the development of hybrid cells followed by the generation of hybrid plants. The hybridity can only be established from euploid and not from aneuploid hybrids.

So, after performing these steps we get the hybrid species.
Hence, the correct answer is option (D).

Note: Sometimes, the production of full-fledged hybrids through the fusion of protoplasts of remotely related higher plant species becomes difficult due to instability of the two dissimilar genomes in a mutual cytoplasm. This phenomenon is referred to as somatic incompatibility.
Whereas, the nucleus is derived from only one parent and the cytoplasm is derived from both the parents are referred to as cybrids. These are cytoplasmic hybrids.