Question

When red flowered plants are crossed with white flowered plants, the $F_2$ generation gives a ratio of 3:1. What do you conclude?

• A. That there are lethal genes
• B. That there is independent assortment
• C. That white colour is dominant
• D. That red colour is dominant

Answer 1

The correct option is D That red colour is dominant

When red coloured flowers crossed with white coloured flowers are giving an F${}_2$ ration of 3:1, it ensures that the red colour is dominant. In the case of co-dominance, the F${}_2$ produced will have pink flowers along with white and red flowers. The ratio will account to 1:2:1 (1 Red : 2 Pink: 1 white). When red is dominant, even if a single R allele is present, the flower will have a red phenotype.