What method is used to establish the genotype of individuals that do not differ in phenotype?

To establish the genotype of individuals that do not differ in phenotype, use the so-called analyzing crosses. In this case, the individual whose genotype must be established is crossed with the individual homozygous for the recessive gene (aa). For example, in order to find out which of the pea plants with yellow seeds have the AA genotype, and which ones are Aa, they should be crossed with the plant with green seeds (aa). If the offspring will have only yellow peas, it means that the studied plant was dominant homozygous (AA). If, in the offspring, splitting into plants with yellow and green peas is observed in a ratio of 1: 1, then the studied plant was heterozygous (Aa).
Analyzing crossbreeding is one of the main methods to determine the genotype of an individual; therefore, it is widely used in genetics and selection.