Question

In a particular plant species, majority of the plants bear purple flowers. Very few plants bear white flowers. No intermediate colours are observed. If you are given a plant with purple flowers, how would you confirm that it is a pure breed for that trait? Explain.

Answer 1

The genotype of a purple flowered plant can be determined by conducting a test cross.

Case I:

If the F1 generation produces all purple flower the parent would be homozygous dominant, i.e., pp.

Case II:

If the F1 generation produces purple and white flowers in 1:1 ratio, the parent would be heterozygous, i.e., Pp.