Question

Flag leaf clipping in hybrid seed production in rice is a regular practice. It is done to achieve-

• A. Higher seed set due to better pollination
• B. Synchronization of flowering
• C. Adjustment of plant height of parental lines
• D. Better seed quality

Hint:

Flag leaf clipping physically removes the leaf barrier around the panicle of the maternal line, allowing air-borne pollen to reach the stigmas and increasing outcrossing rates.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Hybrid rice seed production relies on outcrossing between a male-sterile female line (A-line) and a restorer male line (R-line).
Because rice is naturally self-pollinating, physical barriers that impede cross-pollination must be managed to maximize seed yield.

Step 2: Detailed Explanation:
The flag leaf is the uppermost leaf of the rice plant, located immediately below the emerging panicle.
Because it stands upright and is relatively long and broad, the flag leaf can physically block the path of wind-borne pollen from the male parent (R-line) to the stigmas of the female parent (A-line).
To overcome this physical barrier, the upper half of the flag leaves on the female line is clipped off using sickles or specialized shears during the late boot stage to early panicle emergence stage.
This practice, called flag leaf clipping, offers several benefits:
1. It exposes the emerging panicle, increasing the surface area accessible to pollen.
2. It facilitates uniform wind movement across the canopy, improving the dispersal and deposition of pollen onto the feathery stigmas of the female line.
3. It increases outcrossing rates, leading to a higher seed set and increased hybrid seed yield.
While other agronomic practices manage flowering synchronization (like nitrogen application) or plant height (like GA\(_3\) application), flag leaf clipping specifically addresses mechanical barriers to pollination.

Step 3: Final Answer:
Hence, flag leaf clipping is done to achieve a higher seed set due to better pollination.