Question

A cross between a plant with red flowers and a plant with white flowers yielded 47 plants with red flower and 51 plants with white flowers. What are the genotypes of the parent plants?

Answer 1

Answer:

One of the parents is heterozygous for red (Rr) and the other is homozygous for white (rr)

Explanation:

The ratio of red flowers to white flowers is roughly 50:50 in this cross (51:47)

Assuming red is the dominant trait, and white is the recessive trait, the parents would be Rr (heterozygous red) x rr (homozygous white).

The resulting punnet square (attached) shows that the genotypes are 50% Rr and 50% rr, which would be 50% red and 50% white. Therefore the parents are RR and Rr.

If red is the recessive phenotype, then the opposite would be true, the white parent would be heterozygous and the red parent would be homozygous.

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