In pea plants tall plants t are dominant to dwarf plants. Two heterozygous plants are crohssed. If they have 80 offsprings, how many plants should be dwarf sized? How many will be tall? Give a number, not a percent. Show a Punnett Square to support your answer

Dwarf plants should be 20

Tall plants should be 60

Explanation:

This question involves a single gene coding for height in pea plants. The tall allele (T) is dominant over the allele (t). This means that T will always mask the expression of t in a heterozygous state.

Heterozygous state implies a plant that contains both dominant and recessive alleles i.e. Tt. Using a punnet square, two heterozygous pea plants (Tt × Tt) will produce four possible offsprings with genotypes: TT, Tt, Tt and tt.

TT, Tt, Tt are all phenotypically tall while the are phenotypically dwarf. Hence, a 3 Tall : 1 dwarf ratio was obtained. The phenotypic ratio can be used to determine the amount expected in offsprings.

Out of 80 offsprings, 1/4 × 80 will be dwarf i.e. 20

Out of same 80 offsprings, 3/4 × 80 = 60 will be produced.