Question

Match List - I with List - II.

Choose the correct answer from the options given below:

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

Hint:

Endoreduplication is the "Copy-Paste" of DNA without a new cell. Uninucleate Pollen is the "Sweet Spot" for starting androgenesis.

Answer 1

The Correct Option is B

Concept: This matching exercise links specific cytogenetic phenomena with their respective applications and origins in plant biotechnology.

Step 1: Chromosomal Phenomena (A-III and C-II).
Somatic polyploidy (A) in plant tissues often occurs through endoreduplication (III), a process where the genome replicates multiple times without cell division. This is common in certain differentiated tissues. Conversely, callus-derived plants (C) are famous for exhibiting high levels of genetic variations (II) (somaclonal variation), because the disorganized callus phase is inherently unstable.

Step 2: Haploidy and Breeding (B-IV and D-I).
The most effective source for haploid production (B) is the uninucleate pollen (IV) stage. At this specific point in development, the microspore is most receptive to being "reprogrammed" from gametic to sporophytic growth. Finally, the chromosome doubling of microspore-driven embryos (D) is the essential final step in dihaploid production (I), converting a sterile haploid into a fertile, 100% homozygous diploid.