The corn plant contains three dominant alleles such as A, C, and R in order to produce colored seeds. When a colored plant is tested with three different tester plants, the results are as follows:
| Cross | Results | Conclusion |
| A/-; C/-; R/-; X a/a; c/c; R/R | 50% colored | Colored or white will depend on A and C genes. Half the seeds are colored shows that one of the gene is heterozygous |
| A/-; C/-; R/- X a/a; C/C; r/r | 25% colored | The color of the seeds depends on the expression of the genes A and R in this cross. If any one of the gene is heterozygous then 50% of the seeds would be colored. Since there is only a 25% colored seed both A and R are heterozygous. The colored plant is A/a; C/C; R/r |
| A/-; C/-; R/- X A/A; C/C; r/r | 50% colored | This supports the above conclusion |