This question seems incomplete, but I see your screenshot. My thought are that you have a purebred tall (T) plant and a purebred dwarf (t) plant in the P generation.That cross would be TT x tt and yields an F1 generation of all tall (Tt) plants. Therefore the recessive trait would not be expressed in the F1 generation. Tall (Tt) = 100% or a 4:0 ratio. See attached Punnett square.