question_answer

In a monohybrid cross involving incomplete dominance the phenotypic ratio equals the genotypic ratio in \[{{F}_{2}}\] generation. The ratio is

A)                  3 : 1                                      

B)                  1 : 2 : 1

C)                  1 : 1 : 1 : 1                           

D)                  9 : 7

Correct Answer: B

Solution :

                When F1 hybrids exhibited a mixture or blending of characters of two parents, the case is considered as that of incomplete or blending inheritance. It simply means that two genes of allelomorphic pair are not related as dominant or recessive, but each of them express itself partially, eg, in the case of 4 Oclock plant (.Mirabilis jalapa) when plants with red flower (homozygous RR) are crossed with plants having white flower (homozygous rr), the heterozygous F, hybrid (Rr) bear pink flower. When these pink flowers are self-pollinated, they develop red (RR), pink (Rr) and white (rr) flowers in the ratio 1:2:1 respectively genotypic ally as well as phenotypically.