In four-o’clock plants, two genes, Y and R, affect flower color. Neither is comp
ID: 64591 • Letter: I
Question
In four-o’clock plants, two genes, Y and R, affect flower color. Neither is
completely dominant, and the two interact with each other to produce seven different flower
colors:
Y/Y R/R = crimson
Y/y R/R = magenta
Y/Y R/r = orange-red
Y/y R/r = magenta-rose
Y/Y r/r = yellow
Y/y r/r = pale yellow
y/y R/R, y/y R/r, and y/y r/r = white
a. In a cross of a crimson-flowered plant with a white one (y/y r/r) what will the appearances F1
plants, the F2 plants, and the offspring of the F1 plants backcrossed to their crimson parents be?
b. What will the flower colors in the offspring of a cross of orange-red X pale yellow be?
c. What will the flower colors in the offspring of a cross of a yellow with a y/y R/r white be?
Explanation / Answer
a.
Thus, the phenotype of F1 offsprings is magenta-rose that is crossed with crimson flower plant to produce F2 offsprings. The phenotypic ratio of F2 offsprings is 1:1:1:1.
b.
Thus, the phenotypic ratio of offsprings is 1:1:1:1.
c.
Thus, the phenotypic ratio of offsprings is 1:1.