Question

Application of which of the following is recommended to take care of pops (unfilled pods) in groundnut?

• A. Gypsum
• B. Borax
• C. Copper sulphate
• D. Zinc

Hint:

Associate "pops in groundnut" with "Calcium deficiency."
Because Gypsum is the most common and cost-effective calcium fertilizer used in groundnut cultivation, it is the standard answer.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The groundnut (Arachis hypogaea) has a unique fruiting habit called geocarpy, where the fertilized ovary (peg) elongates and penetrates into the soil to develop into a pod.
Proper shell and kernel development require specific nutrients directly available in the soil zone where the pods are developing.

Step 2: Detailed Explanation:
"Pops" is a physiological disorder in groundnut characterized by the formation of normal-looking pods that are empty or contain shriveled, underdeveloped kernels.
This disorder is primarily caused by a deficiency of Calcium (Ca) in the pod-zone of the soil during the early pegging and pod-forming stages.
Groundnut plants cannot translocate calcium downward from the leaves through the peg to the developing pod.
Therefore, the developing pod must absorb calcium directly from the surrounding soil.
To prevent this, the application of Gypsum (\(\text{CaSO}_4 \cdot 2\text{H}_2\text{O}\)) at the rate of \( 250 - 400 \, \text{kg/ha} \) is highly recommended close to the plant root zone (broadcasting or side-dressing) at the peak flowering or early pegging stage (around 40-45 days after sowing).
Gypsum serves as an excellent, highly soluble source of both Calcium (\( \sim 22\% \)) and Sulphur (\( \sim 18\% \)), which are essential for oil synthesis and complete kernel filling, thereby eliminating the "pops" problem.

Step 3: Final Answer:
Gypsum application is recommended to prevent pops in groundnut.