Question

Which of the following statement is NOT correct with respect to Cybrids?

• A. They are the resultants of spontaneous fusion of protoplasts obtained from common callus culture
• B. They allow the direct transfer of cytoplasmic male sterility (CMS) from donor to recipient
• C. The process can bypass up to 12 backcrosses required in development of alloplasmic lines
• D. It is a fusion of protoplast of one parent and cytoplast of the second

Hint:

• Cybrid = Nucleus (one parent) + Cytoplasm (another)
• Used for cytoplasmic trait transfer (e.g., CMS)
• Not formed by spontaneous fusion

Answer 1

The Correct Option is A

Concept: Cybrids (cytoplasmic hybrids) are formed by combining the nucleus of one cell with the cytoplasm of another. This is typically achieved through protoplast fusion where one cell contributes nucleus and the other contributes cytoplasm.
• Used for transfer of cytoplasmic traits like cytoplasmic male sterility (CMS).
• Helps avoid repeated backcrossing in plant breeding.

Step 1: Analyzing each statement.

• Statement (A): Describes spontaneous fusion from common callus culture → Incorrect, as cybrids are produced through controlled protoplast fusion, not spontaneous fusion.
• Statement (B): Allows transfer of CMS → Correct.
• Statement (C): Reduces need for multiple backcrosses → Correct.
• Statement (D): Fusion of protoplast of one parent and cytoplast of another → Correct definition of cybrid.

Step 2: Selecting the incorrect statement.
Only statement (A) is incorrect.