If Mendel had self-pollinated a tall F₂ plant, what would be the possible genotypes of the offspring?

Fi : Tt crossed with Tt

Gametes : T and t    - T and t 

F2:  TT: Tt:Tt:tt (3 tall and 1 dwarf)

F2 tall plant can be TT ot Tt: 

a) TT crossed with TT - all TT plants 

b) Tt crossed with Tt - 3/4 Tall and 1/4 dwarf plants.

So, we get tall (TT) tall (Tt) and dwarf (tt) plants in such a cross.