Hint: A cybrid is a eukaryotic cell line produced by the fusion of a whole cell with a cytoplast. This fusion is useful in the study of cytoplasmic genes and overcomes sexual incompatibility barriers.
A cybrid is a hybrid of cells or plants containing the genome of one species but cytoplasm of both species. A cybrid is also known as a cytoplasmic hybrid. The technique to produce cybrid is known as cybridization. A cytoplasmic hybrid eukaryotic cell is produced by introducing nuclear material from one organism into a cell from which the nucleus has been removed.
Characteristics of cybridization are-
-This fusion appears to be the only means through which two different parental genomes are often recombined among plants that can't reproduce sexually (asexual or sterile).
-Protoplasts of sexually sterile (haploid, triploid, and aneuploid) plants are often fused to supply fertile diploids and polyploids.
-This fusion overcomes sexual incompatibility barriers. In some cases somatic hybrids between two incompatible plants have also developed utilization in industry or agriculture.
-This fusion is useful in the study of cytoplasmic genes and their activities and this information can be applied in plant breeding experiments.
So, the correct answer is, ‘Cytoplasms of two different plants and the genome of one plant’.
Note: Cybrids are valuable in mitochondrial research and have been used to provide suggestive evidence of mitochondrial involvement in Alzheimer's disease, Parkinson's disease, and other conditions. Recently, the House of Lords passed the Human Fertilisation and Embryology Act 2008, which permits the formation of mixed human-animal embryos for medical purposes only.