Question

in tomatoes, red fruit (r) is dominant over yellow fruit (r). a plant that is heterozygous for red fruit is crossed with a plant that has yellow fruit. what percent of the offspring will be yellow fruit?
100%
25%
75%
50%

Explanation:

Step1: Determine the genotypes of the parents

The heterozygous red - fruit plant has the genotype \(Rr\) (since red \(R\) is dominant and it is heterozygous). The yellow - fruit plant has the genotype \(rr\) (because yellow is recessive and to express the recessive trait, the plant must have two recessive alleles).

Step2: Set up the Punnett square

Gametes of \(Rr\)	Gametes of \(rr\)
\(r\)	\(r\)

The possible offspring genotypes from the cross \(Rr\times rr\) are obtained by combining the gametes. The combinations are \(Rr\) and \(rr\).

Step3: Calculate the proportion of yellow - fruit offspring

The genotype \(rr\) gives yellow fruit. Out of the two possible genotypes (\(Rr\) and \(rr\)) from the cross, the proportion of \(rr\) is \(\frac{1}{2}\) or \(50\%\)

Answer:

\(50\%\)