A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of -
- 3 : 1 :: Tall : Dwarf
- 1 : 2 : 1 :: Tall heterozygous : Tall homozygous : Dwarf
- 1 : 2 : 1 :: Tall homozygous : Tall heterozygous : Dwarf
- 3 : 1 :: Dwarf : Tall
Answer
(3) 1 : 2 : 1 :: Tall homozygous : Tall heterozygous : Dwarf
Solution
P: TT (tall) tt (dwarf)
⇒ F1: all Tt (tall)
⇒ F1 selfed: Tt Tt
∴ F2 genotypes: 1 TT : 2 Tt : 1 tt
= 1 tall homozygous : 2 tall heterozygous : 1 dwarf
(3 : 1 is the phenotypic ratio, not the genotypic ratio.)
Answer: (3)