Define Mendel’s law of segregation. Draw only Punnett’s square to explain this law.

Explanation

The law of segregation states that the two alleles for a character do not blend in an individual but separate into different gametes at the time of gamete formation. (gametogenesis) The law of segregation can be deduced from monohybrid cross.
A cross is performed between a pure tall pea plant and dwarf pea plant. The plants of F, generation are all hybrid tall (Tt) though they have received the factor (gene) for dwarfness. If the hybrids are selfed.

The plants of second filial or F, generation, appear to have both tall and dwarf in the phenotypic ratio of 3: 1. Further self breeding of these F, plants, shows that the dwarf plants breeds true and produce only dwarf plant (tt). Amongst tall plants 1/3 breed true i.e., produce only tall plants (TT), ile the remaining 2/3 of the F, tall plants behave as hybrids (Tt) and produce both tall and dwarf 1:1 in the ratio of 3:1. Therefore the F, phenotypic ratio of 3:1 is genotypically, 1 pure tall (TT): hybrid tall (Tt): 1 dwarf (tt).