a) The Punnett square for the cross between two plants with genotype Tt and Tt is shown below:
T | t
--|--
T | TT
t | Tt
t | t
--|--
T | Tt
t | tt
The genotype ratio for this cross is 1:2:1 (TT:Tt:tt) as shown in the Punnett square.
b) The genotype ratio for this cross is 1:2:1 (TT:Tt:tt) as shown in the Punnett square.
c) The phenotype ratio for this cross is 3:1 (tall:short). This is because the T allele is dominant and masks the expression of the t allele in heterozygotes. Therefore, 3/4 of the offspring will have tall stems and 1/4 will have short stems.