Write the schematic representation of dihybrid cross and mention the result.

Explanation

Law of independent assortment can be studied by means of dihybrid cross (eg) between pure breeding pea plants having yellow round seed (YYRR) and pure breeding pea plant having green wrinkled seed (yyrr). The plants of first filial or F1 generation have all yellow and round seed (YyRr). At the time of gamete formation, according to the law of segregation, each parent produce one gamete YR and yr. The F1 generation shows one contrasting dominant character. On self-breeding, the resultant second filial or F2 generation show four type of gametes YR, Yr, yR, yr. Fusion occurs between any two of these gametes, thus 16 combinations were possible in a `9:3:3:1` phenotypic ratio. The genotypic ratio shall be `1:2:2:4:1:2:1:2:1.` This experiment clearly shows that the genes for the seed characters are assorted independently of each other and the presence of one factor does not contaminate the other.
`{:("Parent Yellow round seed green wrinkled seed"),(" YYRR yyrr"):}`

Phenotypic Ratio :
`{:("Round yellow",:,"Round green",:,"wrinkled yellow",:,"wrinkled green"),(" 9",:," 3",:," 3",:," 1"):}`