Given below are two statements, one is labeled as Assertion (A), and the other one is labeled as Reason (R).
Assertion (A) : Screening of rice for resistance to stem borer is greatly facilitated in the off-season as compared to that in the main growing season.
Reason (R) : In the off-season, few alternate hosts are available for the female moths of the stem borer to lay eggs and hence much heavier infestation occurs in the off-season rice.
Assertion (A) : Screening of rice for resistance to stem borer is greatly facilitated in the off-season as compared to that in the main growing season.
Reason (R) : In the off-season, few alternate hosts are available for the female moths of the stem borer to lay eggs and hence much heavier infestation occurs in the off-season rice.
Show Hint
- Both (A) and (R) are correct and (R) is the correct explanation of (A).
- Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
- (A) is correct but (R) is not correct.
- (A) is not correct but (R) is correct.
The Correct Option is A
Solution and Explanation
To screen crop varieties for resistance to insect pests, researchers require a uniform and heavy pest infestation.
This ensures that susceptible lines are clearly identified and false-positives (escapees) are minimized.
Step 2: Detailed Explanation:
Let us analyze the Assertion and the Reason:
- Assertion (A) is correct: In rice breeding, screening germplasm lines for resistance to the yellow stem borer (*Scirpophaga incertulas*) is highly effective when conducted during the off-season rather than the main cropping season.
- Reason (R) is correct: During the main growing season, extensive agricultural fields are covered with various host crops and vegetation, dispersing the insect population over a large area.
In contrast, during the off-season, agricultural fields are mostly fallow, and alternative host plants are scarce.
Consequently, female stem borer moths are attracted to the limited, isolated off-season rice plots to lay their eggs.
This results in a concentrated, uniform, and heavy pest pressure in the off-season screening nursery, which facilitates the accurate identification of resistant genotypes.
- Analysis of Explanation: The concentrated, heavy pest infestation caused by the lack of alternate hosts during the off-season (as stated in the Reason) is the direct cause of the improved screening efficiency (as stated in the Assertion).
Therefore, Both (A) and (R) are correct, and (R) is the correct explanation of (A).
Step 3: Final Answer:
Both (A) and (R) are correct, and (R) is the correct explanation of (A).
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