Biology Question on Principles of Inheritance and Variation

Question

Incomplete dominance is shown by

Answer 1

Solution

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