Question

Given below are two statements:
Statement I: Explosive epidemics are caused by foliar pathogens that are clonally reproduced.
Statement II: Clonal reproduction allows genetically non-identical virulent types.

In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement I and Statement II are correct
• B. Both Statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but Statement II is correct

Hint:

- Clonal/Asexual reproduction = Rapid multiplication = Genetically identical progeny (no variation).
- Sexual reproduction = Genetic recombination = Genetically diverse progeny.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Epidemiology studies how pathogens spread in plant populations.
Pathogens that reproduce rapidly via asexual (clonal) cycles are often polycyclic and can trigger devastating, fast-spreading foliar epidemics.
Detailed Explanation:
Let us evaluate both statements:
Statement I:
Foliar pathogens such as rusts (Puccinia spp.), powdery mildews, and late blight of potato (Phytophthora infestans) can produce massive numbers of asexual spores (conidia/sporangia) in short generation times.
This clonal (asexual) multiplication allows the pathogen population to explode under favorable microclimatic conditions, initiating explosive polycyclic epidemics.
Thus, Statement I is correct.
Statement II:
Clonal reproduction is a process of mitotic division, which produces progeny that are genetically identical to the parent.
It does not facilitate genetic recombination; thus, it does not allow genetically non-identical virulent types to emerge unless a mutation occurs.
Genetically non-identical types are primarily generated through sexual reproduction, parasexual recombination, or mutation.
Thus, Statement II is incorrect.

Step 2: Final Answer:
Statement I is correct, but Statement II is incorrect.
Therefore, the correct option is (C).