Given below are two statements:
• [Statement (I):] Vertical resistance is exploited in agriculture by pathologists and breeders for crop improvement.
• [Statement (II):] Vertical resistance is mostly monogenic in nature.
In light of the above statements, choose the most appropriate answer from the options given below.
Given below are two statements:
• [Statement (I):] Vertical resistance is exploited in agriculture by pathologists and breeders for crop improvement.
• [Statement (II):] Vertical resistance is mostly monogenic in nature.
In light of the above statements, choose the most appropriate answer from the options given below.
Show Hint
- Vertical Resistance: Monogenic/Oligogenic, race-specific, unstable (can be broken down quickly), complete protection.
- Horizontal Resistance: Polygenic, race-non-specific, stable, partial/moderate protection.
- Both Statement (I) and Statement (II) are correct.
- Both Statement (I) and Statement (II) are incorrect.
- Statement (I) is correct but Statement (II) is incorrect.
- Statement (I) is incorrect but Statement (II) is correct.
The Correct Option is A
Solution and Explanation
J.E. Vanderplank classified plant disease resistance into two types: vertical resistance and horizontal resistance.
Vertical resistance (also called qualitative, specific, or race-specific resistance) is effective against only specific races of a pathogen.
Step 3: Detailed Explanation:
Let us evaluate the statements:
- Statement (I) is correct: Breeders and plant pathologists actively use vertical resistance in crop breeding programs.
It provides complete, high-level resistance against specific pathogen races.
This resistance is easy to select for and introduce into elite crop cultivars to protect them from disease epidemics.
- Statement (II) is correct: Vertical resistance is typically controlled by a single major gene (monogenic) or a few genes (oligogenic).
It follows Harold Flor's "gene-for-gene" model, where a specific resistance gene (R-gene) in the host interacts with a corresponding avirulence gene (avr-gene) in the pathogen to trigger a defense response.
Because it is controlled by a single gene, this resistance is easy to manipulate in breeding programs, but it can be broken down if a new race of the pathogen mutates and overcomes the host's R-gene.
Therefore, both statements are correct.
Step 4: Final Answer:
Both Statement (I) and Statement (II) are correct, matching Option (A).
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