Below is a section of a corncob. This represents the colors…

Below is a section of a corncob. This represents the colors and shapes of the grains produced in the dihybrid F2 results of a cross. [the number of grains is not representative] The characters are ‘grain shape’ and ‘grain color.’ Round shape is dominant to wrinkled shape, and purple color is dominant to yellow color.     What is the expected genotype ratio for the F2 generation of a dihybrid cross?