Chapter 12, Problem 8TYK

Summary Introduction

To review:

The reason why the organisms that are phenotypically alike have a tendency to produce different ratios of progeny phenotypes.

Introduction:

A test cross is used to determine the phenotypes of the parents. It is done by crossing the parent plant with a plant having the recessive genotype. If the ratio of the dominant to recessive genotype in the progeny is $3:1$, then the parent is a true-breeding dominant whereas, if the ratio is $2:2\text{ or }1:1$, then, the parent is heterozygous. This cross gives different phenotypic ratios of the progeny that are phenotypically alike.