Question

in pea plants tall dominate short. what would be the phenotypic ratio of the offspring from a cross of a homozygous tall plant and a short plant.
○ 3 short : 1 tall
○ 3 tall: 1 short
○ 2 tall: 2 short
○ all tall

Explanation:

Step1: Define Genotypes

Let \( T \) represent the dominant tall allele and \( t \) represent the recessive short allele. A homozygous tall plant has genotype \( TT \), and a short plant (recessive) has genotype \( tt \).

Step2: Determine Gametes

The homozygous tall plant (\( TT \)) can only produce gametes with the \( T \) allele. The short plant (\( tt \)) can only produce gametes with the \( t \) allele.

Step3: Perform the Cross

When we cross \( TT \) (tall) and \( tt \) (short), all offspring will have the genotype \( Tt \) (since each offspring gets one \( T \) from the tall parent and one \( t \) from the short parent).

Step4: Determine Phenotype

The \( T \) allele is dominant, so any plant with at least one \( T \) allele will be tall. Since all offspring have genotype \( Tt \), all of them will be tall.

Answer:

All tall