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 bearing purple flowers, how would you ascertain that it is a pure breed for that trait? Explain.

Explanation

To ascertain whether the plant is of pure breed for purple coloured flowers a test cross will be made. In a test cross the given purple coloured plant will be crossed with homozygous plant with white flowers. If all the flowers of the progeny are purple, the plant is homozygous dominant