In Antirrhinum (dog flower), phenotypic ratio in `F_(2)` generation for the inheritance of flower colour would be

Options

A. `3:1`
B. `1:2:1`
C. `1:1`
D. `2:1`

Answer

B

Explanation

The inheritance of flower colour in the Antirrhinum majus (snapdragon or dog flower) is an example of incomple or partial dominance. Imcomplete dominance is the phenomenon in which neither of the two alleles of a gene is completely dominant over the other. In a cross between true-breeding red-flowered (RR) and true-breeding white-flowered plants (rr)m the `F_(1)` plants obtained were pink (Rr) coloured. When the `F_(1)` plants were self-pollinated, the `F_(2)` generation resulted in the ratio, 1 (RR) Red : 2 (Rr) Pink : 1 (rr) white. The phenotypic ratios had changed from the normal 3 : 1 dominant : recessive ratio to `1:2:1` R. was not completelt dominant over r and this made it possible to distinguish Rr (pink) from RR (red) and rr (white).