Question

What is the optimal average temperature at the time of wheat maturity?

• A. 20-25°C
• B. 16-22 °C
• C. 14-15 °C
• D. 8-10 °C

Hint:

Remember the general rule of thumb for rabi crops like wheat: "Cool, moist weather during growth, and warm, dry, sunny weather during maturity."
This helps identify \( 20-25^\circ\text{C} \) as the mature ripening temperature.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Wheat (Triticum aestivum) is a rabi crop that requires distinct climatic conditions during different physiological growth stages: germination, tillering, jointing, flowering, and grain filling/maturity.

Step 2: Detailed Explanation:
The temperature requirements for wheat shift significantly throughout its life cycle:
- Germination: Optimum temperature is \( 20 - 22^\circ\text{C} \).
- Vegetative growth and tillering: Cool climate with temperatures of \( 16 - 22^\circ\text{C} \) is ideal.
- Grain ripening and maturity: Warm, dry, and sunny conditions are required.
At the time of maturity (grain filling and ripening), the optimal average temperature range is \( 20 - 25^\circ\text{C} \).
Temperatures in this range facilitate proper starch deposition, accelerate senescence of photosynthetic organs, and dry the grain down to a safe moisture level for harvesting.
If temperatures rise too rapidly above \( 30^\circ\text{C} \) during this phase (terminal heat stress), it leads to premature forced maturity, resulting in shriveled grains and reduced yields.
Extremely low temperatures (such as \( 8 - 15^\circ\text{C} \)) would delay ripening and harvest indefinitely.

Step 3: Final Answer:
The optimal average temperature at the time of wheat maturity is 20-25°C.