Inheritance of Two Traits (Law of Independent Assortment)

Inheritance of Two Traits (Law of Independent Assortment)
The study of inheritance of two traits is based on dihybrid cross. It is a cross made between two parents which differ in two pairs of contrasting characters. For example Mendel made a cross between a pure breeding pea plant having round and yellow seeds wiwth a pure breeding plant with wrinkled and greeen seeds. The result showed that in F1 generation all plants had round seeds with yellow colour (Double dominant). When these plants were allowed to self fertilize, the F2 generation showed 4 different varieties in the following ratio
F2
Round Yellow …….. 9
Round Green …….. 3
Wrinkled Yellow …….. 3
Wrinkled Green …….. 1
This F2 phenotypic ratio of 9:3:3:1 is called dihybrid ratio.