Two new mutant lines of a flowering plant have been obtained; one breeds true for blue flower color and the other breeds true for red flower color (wild-type flower color is purple). Consider the following crosses.
1. blue $\times$ purple $\rightarrow F _ { 1 }$ all purple $\rightarrow F _ { 2 } 75 \%$ purple; $25 \%$ blue
2. red $\times$ purple $\rightarrow \mathrm { F } _ { 1 }$ all purple $\rightarrow \mathrm { F } _ { 2 } 75 \%$ purple; $25 \%$ red
3. red $\times$ blue $\rightarrow F _ { 1 }$ all purple

If the red pigment is a precursor of the purple pigment,the blue pigment is a precursor of the red pigment,and a colorless compound is the precursor of the blue pigment in a linear biosynthetic pathway controlling flower color,what phenotypic ratios do you expect in the F₂ of cross 3?

Question

Two new mutant lines of a flowering plant have been obtained; one breeds true for blue flower color and the other breeds true for red flower color (wild-type flower color is purple). Consider the following crosses.
1. blue

\times

purple

\rightarrow F _ { 1 }

all purple

\rightarrow F _ { 2 } 75 \%

purple;

25 \%

blue
2. red

\times

purple

\rightarrow \mathrm { F } _ { 1 }

all purple

\rightarrow \mathrm { F } _ { 2 } 75 \%

purple;

25 \%

red
3. red

\times

blue

\rightarrow F _ { 1 }

all purple

If the red pigment is a precursor of the purple pigment,the blue pigment is a precursor of the red pigment,and a colorless compound is the precursor of the blue pigment in a linear biosynthetic pathway controlling flower color,what phenotypic ratios do you expect in the F₂ of cross 3?