Explanation

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 or allelomorphic pair are not related as dominant or recessive, but each of them expresses itself partially partially. For example, in 4 O’clock plant $(Mirabilis\ jalapa)$,when plants with red flower (homozygous,RR) are crossed with plants having white flower (homozygous,rr),the herterozygous $F_{1}$-hybrid (Rr) bear pink flower.