Question

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Whip tail physiological disorder is caused due to molybdenum deficiency in cauliflower.
Reason R: The occurance of whip tail disorder particularly in the soil pH above 5.5.
In light of the above statements, choose the correct answer from the options given below:

• A. Both A and R are correct and R is the correct explanation of A
• B. Both A and R are correct but R is NOT the correct explanation of A
• C. A is correct but R is not correct
• D. A is not correct but R is correct

Hint:

Molybdenum deficiency causes Whiptail in cauliflower.
Unlike most micronutrients, molybdenum availability decreases in acidic soils (pH $< 5.5$) and increases in alkaline soils.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Micronutrient availability in soil is regulated by soil pH.
Molybdenum ($\text{Mo}$) is an essential micronutrient needed by cauliflower for nitrogen metabolism and leaf development.
Its availability decreases in highly acidic soils.

Step 2: Detailed Explanation:
Assertion A is correct.
Whiptail is a physiological disorder in cauliflower caused by a deficiency of available molybdenum.
Affected plants develop thin, strap-like leaves with restricted lamina growth, leaving only the thick midrib, which resembles a whip.
Reason R is incorrect.
Molybdenum becomes chemically bound and unavailable to plants in acidic soils, typically with a pH below $5.5$.
The disorder occurs primarily in highly acidic soils (pH $< 5.5$).
Liming acidic soils to raise the pH above $6.0$ increases molybdenum availability and prevents the disorder.
Therefore, the statement that whiptail occurs in soil pH above $5.5$ is factually incorrect.

Step 3: Final Answer:
Assertion A is correct, but Reason R is not correct, which corresponds to Option (C).