Question

Match List I with List II
List I (Process):
A. Anther culture
B. Asymmetric hybrid
C. Analytical breeding
D. Actinomycin D
List II (Results/Related to):
I. Virus elimination
II. Gamatoclonal variation
III. Chromosome elimination
IV. Ploidy manipulation
Choose the correct answer from the options given below:

• A. A - I, B - III, C - IV, D - II
• B. A - II, B - III, C - IV, D - I
• C. A - II, B - III, C - I, D - IV
• D. A - II, B - IV, C - III, D - I

Hint:

Remember that "gametoclonal variation" specifically refers to variation arising from gametes (hence microspores/anthers), while "somatoclonal variation" refers to somatic cells. This directly connects anther culture to gametoclonal variation.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
This question covers various plant breeding, tissue culture, and therapeutic techniques used to induce genetic variation, modify ploidy levels, or cure viral infections.

Step 2: Detailed Explanation:
Let us establish the correct association for each item:
A. Anther culture: This technique involves culturing anthers containing microspores to produce haploid plants.
The phenotypic and genotypic variation observed among the plants regenerated from gametic cells (such as pollen or microspores) is termed gametoclonal variation.
Therefore, A matches with II (Gamatoclonal variation).
B. Asymmetric hybrid: Asymmetric somatic hybridization is achieved by fusing protoplasts where one parent (the donor) has been irradiated with X-rays or gamma rays to fragment its nuclear DNA.
During subsequent cell divisions, preferential loss or chromosome elimination of the irradiated parent occurs, leaving only a few chromosomes or genomic fragments integrated into the recipient genome.
Therefore, B matches with III (Chromosome elimination).
C. Analytical breeding: Proposed by Chase, analytical breeding is a method of ploidy manipulation, especially in polyploid crops like potato.
It involves reducing a polyploid (e.g., tetraploid) to a lower ploidy level (diploid), carrying out breeding and selection at the simpler diploid level, and then doubling the chromosomes back to the tetraploid level.
Therefore, C matches with IV (Ploidy manipulation).
D. Actinomycin D: Actinomycin D is an inhibitor of RNA synthesis and transcription.
In plant tissue culture, antiviral compounds and transcription inhibitors like Actinomycin D are used in combination with meristem culture to suppress viral replication and achieve virus elimination.
Therefore, D matches with I (Virus elimination).

Step 3: Final Answer:
The matches are: A - II, B - III, C - IV, D - I. This corresponds to Option (B).