Question

When two species can not be crossed directly due to incompatibility, a third species is used to make the target gene transfer possible, which is called as-

• A. Parachute species
• B. Backing species
• C. Bridge species
• D. Rescue species

Hint:

When a direct cross is blocked, think of a "bridge" spanning the gap.
A bridge species is compatible with both parents, allowing genetic material to cross between otherwise incompatible species.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Hybridization barriers between different plant species can prevent direct gene transfer, often due to pre-zygotic or post-zygotic incompatibility.
To bypass these barriers, breeders can use intermediate species to facilitate gene flow.

Step 2: Detailed Explanation:
When two target parent species (such as a cultivated crop and a wild relative) cannot be crossed directly due to genetic incompatibility, breeders can employ a third species called a bridge species.
The bridge species is compatible with both target parents, allowing it to act as an evolutionary or genetic "bridge."
The breeder first crosses one of the target parents with the bridge species to generate a fertile hybrid intermediate.
This hybrid intermediate is then crossed with the second target parent to complete the gene transfer.
This multi-step hybridization pathway is known as a bridge cross, and the third species is called a bridge species.
The terms parachute species (A), backing species (B), and rescue species (D) are not used to describe this hybridization strategy.

Step 3: Final Answer:
The compatible intermediate species used to facilitate the cross is called a bridge species, corresponding to option (C).