Question

A dihybrid for qualitative trait is crossed with homozygous recessive individual of its type, the phenotypic ratio is

• A. 1:2:1
• B. 3:1
• C. 1:1:1:1
• D. 9:3:3:1

Answer 1

The correct option is C 1:1:1:1

The given cross is a test cross. The ratio for a test cross is always 1:1(monohybrid cross) and 1:1:1:1 for a dihybrid cross.
For example:
RrYy X rryy
(round, yellow) (wrinkled, green)
RrYy Rryy rrYy rryy
(Round, yellow) (round, green) (wrinkled, yellow) (wrinkled, green)