Question

1. red roses are dominant to white roses, and tall are dominant to short. cross a flower that is homozygous red and tall with a flower that is white and heterozygous tall. what will be the possible genotypes and phenotypes of the offspring? show your work as a punnett square and write your answers as a phenotypic ratio.

Explanation:

Step1: Define alleles and genotypes

Let \(R\) = red (dominant), \(r\) = white (recessive); \(T\) = tall (dominant), \(t\) = short (recessive).

• Homozygous red and tall: \(RRTT\), gametes = \(RT\)
• White and heterozygous tall: \(rrTt\), gametes = \(rT, rt\)

Step2: Set up Punnett square

	\(RT\)	\(RT\)	\(RT\)	\(RT\)
\(rt\)	\(RrTt\)	\(RrTt\)	\(RrTt\)	\(RrTt\)
\(rT\)	\(RrTT\)	\(RrTT\)	\(RrTT\)	\(RrTT\)
\(rt\)	\(RrTt\)	\(RrTt\)	\(RrTt\)	\(RrTt\)

Step3: Count genotypes/phenotypes

• Genotypes: \(RrTT\) (8/16), \(RrTt\) (8/16)
• Phenotypes: All \(Rr-\) = red; \(TT/Tt\) = tall, so all red tall.

Answer:

• Possible genotypes: \(RrTT\), \(RrTt\) (1:1 genotypic ratio)
• Possible phenotypes: All red and tall (phenotypic ratio = 1:0, or 16:0 for red tall:white short)