Gregor Johann Mendel, the father of genetics, crossed a tall pea (TT) with another short pea (tt) to obtain the long pea (Tt) in the F1 lineage. Self-fertilization between tall beans (Tt) in the F1 progeny yielded 3 tall (75%) and 1 short (25%) beans in the F2 progeny.
here,
The gene responsible for the tall trait is T
Consequently, the genotype for the tall trait is TT
again,
The gene responsible for the short trait is t
Consequently, the short trait genotype is tt
The first progeny is F1 and the second progeny is F2
Parents : ♂ × ♀
Phenotype: tall short
Genotype : TT tt
Gamete: T t
1st generation : Tt (tall)
Self fertilition : F1×F1
Parents : ♂ × ♀
Phenotype: tall tall
Genotype : Tt Tt
Gamit : (T), (t) (T), (t)
F2 progeny (checker board)
Comment: From the checker board, out of four beans, 3 are tall and 1 is short.
Phenotypic ratio : Tall : Short = 3:1