Question

Diseases occurring due to Ca deficiency are
(A) Hollow heart in Groundnut
(B) Frenching of Citrus
(C) Pod popping in Groundnut
(D) Pillowing of Cucumber
Choose the correct answer from the options given below :

• A. Only (A) and (B)
• B. Only (B) and (C)
• C. Only (A) and (D)
• D. Only (C) and (D)

Hint:

To prevent pod popping, groundnut farmers apply gypsum ($\text{CaSO}_4\cdot 2\text{H}_2\text{O}$) during the flowering and pegging stages to ensure an abundant supply of soluble calcium in the topsoil layer.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Calcium (Ca) is an essential secondary plant nutrient that provides structural strength to cell walls (as calcium pectate) and regulates membrane permeability.
Calcium deficiency causes specific physiological disorders in crops, particularly affecting actively growing tissues like young leaves, fruits, and pods.

Step 3: Detailed Explanation:
Let us analyze each physiological disorder listed:
- (A) Hollow heart in Groundnut: This disorder is characterized by a dark, hollow cavity in the center of the peanut kernels. It is caused by Boron (B) deficiency, not calcium.
- (B) Frenching of Citrus: This is a condition characterized by chlorotic patches between leaf veins. It is primarily caused by Zinc (Zn) deficiency (or sometimes nitrogen/lead imbalances), not calcium.
- (C) Pod popping in Groundnut: This is a major disorder in groundnut where the pods develop normally on the outside but are completely empty or contain shriveled, undeveloped seeds.
Groundnuts require high calcium levels in the pegging zone to support seed development. A lack of calcium prevents seed formation, causing "pops". (True)
- (D) Pillowing of Cucumber: This is a physiological disorder where the inner tissues of the cucumber fruit break down, forming hollow, spongy, or pillow-like cavities. It is caused by a calcium deficiency that weakens cell walls during rapid fruit growth. (True)
Therefore, only (C) and (D) are caused by calcium deficiency.

Step 4: Final Answer:
The correct option is Only (C) and (D), corresponding to option (D).