Question

What should be the most favorable temperature for tuber formation in potato?

• A. $8^\circ\text{C}$
• B. $12^\circ\text{C}$
• C. $14^\circ\text{C}$
• D. $17^\circ\text{C}$

Hint:

Potato Temperature Cardinal Points:
- Optimum for Tuberization: $17\text{--}18^\circ\text{C}$.
- Optimum for Vegetative Growth: $20\text{--}24^\circ\text{C}$.
- Tuberization Completely Ceases: Above $29\text{--}30^\circ\text{C}$.

Answer 1

The Correct Option is D

Concept:
Potato (Solanum tuberosum) is a temperate, cool-season solanaceous tuber crop.
Its life cycle comprises two distinct thermal phases: vegetative shoot development and tuberization (initiation and swelling of underground stolons into tubers).
Tuberization is highly sensitive to soil and ambient temperatures; high temperatures inhibit the transport and accumulation of photosynthates into developing tubers.

Step 1: Vegetative Growth vs. Tuberization Temperatures:
- For early vegetative sprout emergence and foliar canopy growth, the optimum temperature is approximately $20\text{--}24^\circ\text{C}$.
- For underground stolon induction, initiation, and maximum tuber bulking rate, the optimum soil/ambient temperature is $17\text{--}20^\circ\text{C}$ (specifically centered around $17\text{--}18^\circ\text{C}$).

Step 2: Effects of Temperature Deviations:
- High Temperatures ($>21^\circ\text{C}$): Tuber growth slows down markedly. If temperatures exceed $29\text{--}30^\circ\text{C}$, tuberization completely ceases because assimilated carbohydrates are consumed by enhanced plant respiration rather than stored in tubers.
- Low Temperatures ($<10^\circ\text{C}$): Plant enzymatic activities and tuber growth are severely reduced.

Step 3: Selecting the Optimum Choice:
Among the given values ($8^\circ\text{C}$, $12^\circ\text{C}$, $14^\circ\text{C}$, and $17^\circ\text{C}$), $17^\circ\text{C}$ represents the physiologically optimal temperature for tuber formation.

Step 4: Final Answer:
Thus, the most favorable temperature for tuber formation in potato is $17^\circ\text{C}$, which is option (D).