Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Tuberization in sweet potato is almost absent at 75 % shade and severely affected at 55 % and not much affected at 25 % shade.
Reason (R) : Warm sunny days and cool nights are favourable for better tuber development in sweet potato.
In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

Sweet potato needs a lot of sun for good tuber formation because tubers are stored carbohydrates from photosynthesis. Shade reduces sunlight, thus reducing tuberization (Assertion A).
Warm sunny days (for lots of photosynthesis) and cool nights (to reduce sugar use by the plant itself) are ideal for sweet potato tuber growth (Reason R).
The reason explains the assertion: if sunny days are needed, then lack of sun (shade) will be harmful.

Answer 1

The Correct Option is A

Step 1: Tuber growth depends on surplus carbohydrate from photosynthesis after respiration is subtracted.
Step 2: Shade cuts photosynthesis, so tuberization drops as shade increases, confirming Assertion (A) is true.
Step 3: Warm sunny days boost photosynthesis and cool nights cut respiratory losses, maximising that surplus, confirming Reason (R) is true and that it explains (A).
Step 4: The correct answer is both (A) and (R) are true and (R) is the correct explanation of (A).