In Mirabilis jalapa also known as the 4'o clock plant, flower colour shows incomplete dominance that is why the F1 plant obtained by the crossing of pure Red flowered plant(RR) with pure white flowered plant(rr) shows pink flowers(Rr).
When F1 plant(Rr) is crossed is with pure white flowered plant (rr), the plant obtained would have a genotype of Rr and rr in ratio 2:2
While the phenotype will be 2 pink and 2 white at of 2:2
