Human Heredity 11th Edition by Michael Cummings

Exercise 26

A plant geneticist is examining the mode of inheritance of flower color in two closely related species of exotic plants. One species may have two pure-breeding lines-one produces a distinct red flower, and the other produces flowers with no color at all, or very pale yellow flowers-however, she cannot be sure. A cross of these varieties produces all pink-flowered progeny. The second species exhibits similar pure-breeding varieties; that is, one variety produces red flowers, and the other produces an albino or very pale yellow flower. A cross of these two varieties, however, produces orange-flowered progeny exclusively. Analyze the mode of inheritance of flower color in these two plant species.