Dear student,
In the F1 generation of a monohybrid cross of a tall and a dwarf plant (both of which are homozygous for their character), all plants have the genotype Tt and the phenotype is tall .
In the F2 generation, genotypic ratio obtained is 1:2:1(TT:Tt:tt) and the phenotypic ratio obtained is 3:1(Tall: Dwarf).
Regards.