The correct combination is (2) B and C. Somatic hybridization via protoplast fusion can generate hybrids with variable/asymmetric parental genomes, and it allows transfer of whole chromosomes or gene blocks without needing to isolate specific genes.

Evaluating each statement

A. Protoplasts of only sexually compatible plant species can be fused – False
Somatic hybridization is specifically valuable because it can fuse protoplasts from sexually incompatible or distantly related species, overcoming pre‑ and post‑zygotic barriers of conventional breeding. It is used to create interspecific and even intergeneric hybrids that cannot be obtained by normal sexual crosses. Therefore, limiting fusion to “only sexually compatible species” is incorrect.

B. Hybrids are produced with variable and asymmetric amounts of genetic material of parental species – True
Protoplast fusion can yield symmetric hybrids (nearly full chromosome sets from both parents) as well as asymmetric hybrids, where chromosomes from one parent are partially lost, leading to unbalanced or mosaic nuclear constitutions. This variability and asymmetry in parental genomic contribution is a characteristic feature of somatic hybrids and cybrids.

C. Protoplast fusion permits transfer of gene block or chromosomes – True
Unlike gene‑by‑gene genetic engineering, somatic hybridization typically transfers large chromosomal segments or entire chromosomes, bringing in blocks of linked genes (e.g., disease‑resistance loci, stress‑tolerance regions) from one species into another. This chromosome- or gene‑block transfer is one of the main advantages of somatic hybridization for crop improvement.

D. Genes to be transferred need to be identified and isolated – False
In somatic hybridization, there is no requirement to clone, isolate or even precisely identify individual genes before transfer. Whole genomes or large chromosomal regions are moved together, and desirable recombinants are selected phenotypically or cytogenetically afterward. The condition “genes to be transferred need to be identified and isolated” describes transgenic or molecular cloning approaches, not somatic hybridization.

Option-by-option reasoning

• (1) A and C – Incorrect, because A is false while C is true.

• (2) B and C – Correct; both statements accurately describe the nature of somatic hybrids and the type of genetic transfer achieved.

• (3) A and D – Incorrect; both A and D mischaracterize the technique.

• (4) B and D – Incorrect; B is true but D is false, so the pair does not form a correct combination.

SEO‑oriented introduction (for article use)

Somatic hybridization is a plant‑breeding technique in which isolated protoplasts from different species are fused to produce novel hybrids carrying traits from both parents. Because this process often generates hybrids with variable, asymmetric genomes and moves chromosomal blocks or entire chromosomes rather than isolated genes, the correct statements for exam questions are that hybrids show variable/asymmetric parental genetic material and that protoplast fusion permits transfer of gene blocks or chromosomes (statements B and C).