Principles of Inheritance and Variation
In Mendel's dihybrid experiment, the phenotypic ratio was
A. 9 (round green) : 3 round yellow: 3 [wrinkled yellow]: 1 wrinkled green
B. 9 (round yellow): 3 round green : 3 [wrinkled yellow]: 1 wrinkled green
C. 9 (round yellow): 3 (round green): 3 [round yellow]: 1 wrinkled green
D. 9 (wrinkled green) : 3 (round yellow): 3 wrinkled yellow: 1 round green
B. 9 (round yellow): 3 round green : 3 [wrinkled yellow]: 1 wrinkled green
The cross between two parents differed in two pairs of contrasting traits; is called dihybrid cross.
Mendel also worked with and crossed pea plants that differed in two characters, as is seen in the cross between a pea plant that has seeds with yellow colour and round shape and one that had seeds of green colour and wrinkled shape. The genotype of the parents can then be written as RRYY and rryy.
The phenotypes round, yellow; wrinkled, yellow; round, green and wrinkled, green appeared in the ratio 9:3:3:1.
This derivation can be written as follows: (3 Round : 9 Round, Yellow : 3 Wrinkled, Yellow: 3 Round, Green : 1 Wrinkled, Green.