Question

If 120 plants are produced on crossing pure red (dominant) and pure white (recessive) flowered pea plants, than the ratio of offsprings will be:

• A. 90 Red : 30 White
• B. 30 Red : 90 White
• C. 60 Red : 60 White
• D. All red

Answer 1

The correct option is D All red

Genotype of pure red-flowered (dominant) plant: RR
Genotype of pure white-flowered (recessive) plant: rr

Parent generation: RR x rr
F${}_1$generation: Rr (red flowers)

Thus, from a cross between pure red and pure white-flowered plants, only red-flowered plants are obtained. Hence, all 120 plants obtained from the given cross are red-flowered plants.