Which of the following constitutes 'genetic emasculation'?
A. Genetic male sterility
B. Transgenic male sterility
C. Cytoplasmic-genetic male sterility
D. Chemical hybridizing agent
Choose the correct answer from the options given below:
A. Genetic male sterility
B. Transgenic male sterility
C. Cytoplasmic-genetic male sterility
D. Chemical hybridizing agent
Choose the correct answer from the options given below:
Show Hint
- A, B and D only
- A, B, and C only
- B, C, and D only
- A, C, and D only
The Correct Option is B
Solution and Explanation
Emasculation is the removal or inactivation of male reproductive organs (anthers) to prevent self-pollination in hybrid seed production. "Genetic emasculation" refers to the use of genetically programmed male sterility systems, which removes the need for physical, manual emasculation of flowers.
Step 2: Detailed Explanation:
Let us evaluate each of the given options:
- A. Genetic male sterility (GMS): This system is governed by nuclear male-sterile genes (typically recessive, such as \( ms \)). It is a purely genetic approach that prevents pollen development. Thus, it is a method of genetic emasculation.
- B. Transgenic male sterility: This is created by introducing foreign genes (such as the Barnase gene under a tapetum-specific promoter) to disrupt pollen development. Because the sterility is inherited and controlled genetically, it is a method of genetic emasculation.
- C. Cytoplasmic-genetic male sterility (CGMS): This is governed by the interaction of mitochondrial (cytoplasmic) genes and nuclear non-restorer genes. It is widely used in commercial hybrid seed production and is a genetic method.
- D. Chemical hybridizing agents (CHAs): CHAs are chemical gametocides sprayed on plants to kill or sterilize pollen grains. This is a chemical, agronomic intervention, not a genetic system.
Therefore, options A, B, and C are genetic emasculation methods, while D is not.
Step 3: Final Answer:
Hence, the correct answer is A, B, and C only.
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