3. A dominant gene (Dt) interacts with a_{1} to give dotted aleurone. Dt does not interact with a_{2}, c or r. Seeds of a_{1}^{p} a_{1} A_{2} C R Dt constitution have a pale purple background on which appear the more intense dots. The ratio of the number of dots on seeds of a_{1} a_{1} a_{1}^{p} A_{2} C R Dt Dt dt genotype to the number of dots on seeds of a_{1} a_{1} a_{1} A_{2} C R Dt Dt dt constitution is 2 : 3, while the ratio for seeds of a_{1} a_{1}^{p} a_{1}^{p} A_{2} C R Dt dt dt to seeds of a_{1} a_{1} a_{1} A_{2} C R Dt dt dt constitution is 1 : 3.8. These ratios suggest that the dosage of a_{1} affects the number or else that a_{1}^{P} has an inhibitory effect which is proportional to the dosage of a_{1}^{p}. Dt is not linked but is independent of a_{1}, a_{2}, c, r, su and lg.