Question

Seed dormancy is broken by mechanical scarification in this crop

• A. Cotton
• B. Castor
• C. Coriander
• D. Chickpea

Hint:

Scarification always targets physical dormancy caused by a hard seed coat.
Common methods include rubbing seeds with sandpaper, nicking the seed coat with a file, or treating them briefly with concentrated acid.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Seed dormancy is a physiological state that prevents seeds from germinating even under favorable environmental conditions.
One major cause is physical dormancy, where a hard, impermeable seed coat prevents water and oxygen from entering the seed.
Mechanical scarification is the physical scratching, chipping, or cracking of this hard seed coat to allow water uptake (imbibition) and initiate germination.

Step 2: Detailed Explanation:
Let us evaluate seed coat characteristics and dormancy-breaking methods for the given crops:
Castor (*Ricinus communis*) seeds have a caruncle that absorbs water easily, and they do not require mechanical scarification to germinate, matching Option (B).
Coriander (*Coriandrum sativum*) "seeds" are actually two-seeded fruits (schizocarps) that are split mechanically into two mericarps to improve germination, but this is a splitting process rather than seed coat scarification, matching Option (C).
Chickpea (*Cicer arietinum*) has a seed coat that absorbs water readily without scarification, matching Option (D).
Cotton (*Gossypium* species) seeds, particularly certain varieties and wild species, have a hard seed coat covered in short, dense fibers (linters).
This seed coat is impermeable to water and gases, causing physical dormancy.
To break this dormancy and improve germination rates, cotton seeds are treated with concentrated sulfuric acid (acid scarification) or rubbed with abrasive materials (mechanical scarification) to weaken the seed coat, allowing water to enter.

Step 3: Final Answer:
Seed dormancy is broken by mechanical scarification in Cotton.
This corresponds to Option (A).