If white colour flower of Antirrhinum sp. successfully crossed with the pink colour flower, what would be the proportion of white and pink color flowers in the next generation?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 1:1
In Antirrhinum, flower colour shows incomplete dominance: RR is red, Rr pink and rr white. The cross is white (rr) × pink (Rr).
| Gametes | R | r |
|---|---|---|
| r | Rr (pink) | rr (white) |
Half the offspring are Rr (pink) and half rr (white), so white : pink = 1 : 1.
Option (2) 3:2 — Incorrect. A monohybrid cross cannot give 3 : 2; the classes are always in halves or quarters.
Option (3) 2:3 — Incorrect. The same ratio reversed, and just as impossible.
Option (4) 2:1 — Incorrect. The white parent gives only r, so the two classes are equal, not 2 : 1.