Describe incomplete dominance.

(N/A) Incomplete dominance is a phenomenon where the dominant allele does not completely mask the expression of the recessive allele,resulting in a phenotype that is intermediate between the two homozygous parents.
When experiments on peas were repeated using other traits in other plants,it was found that sometimes the $F_{1}$ generation had a phenotype that did not resemble either of the two parents and was intermediate between the two.
The inheritance of flower colour in the dog flower (Snapdragon or Antirrhinum sp.) is a classic example to understand incomplete dominance.
In a cross between true-breeding red-flowered $(RR)$ and true-breeding white-flowered $(rr)$ plants,the $F_{1}$ $(Rr)$ generation was pink.
When the $F_{1}$ plants were self-pollinated,the $F_{2}$ generation resulted in the following ratio: $1$ $(RR)$ Red : $2$ $(Rr)$ Pink : $1$ $(rr)$ White.
Here,the genotypic ratios were exactly as expected in any Mendelian monohybrid cross $(1:2:1)$,but the phenotypic ratio had changed from the typical $3:1$ dominant:recessive ratio to $1:2:1$.
This occurs because the '$R$' allele is not completely dominant over the '$r$' allele,making it possible to distinguish the heterozygous $Rr$ (pink) from the homozygous $RR$ (red) and $rr$ (white).