Question

A white colour flower plant denoted by WW is cross bred with that of yellow colour flower
plant denoted by ww.
(a) State the colour of flower you would expect in the F1 generation plants.
(b) What must be the percentage of yellow flower plants in F2 generation if flowers of F1 plants
are self-pollinated?
(c) State the expected ratio of the genotypes WW and Ww in the F2 progeny

Answer 1

Given,

The white flower is denoted by WW and the yellow flower is denoted by ww.

Let's do the pedigree analysis:

1. For the F1 generation,

    W    W

w  Ww  Ww

w Ww  Ww

2. For the F2 generation (if F1 plants are self-pollinated)

    W    w

W  WW  Ww

w Ww  ww

Answers:

(a) From the above analysis, the colour of the flower in the F1 generation plants would be white since white is the dominant trait and all the flowers in the F1 generation will have the phenotype Ww.

(b) In the F2 generation, there is 1 yellow flower (ww) out of the 4 flowers, thus the percentage of yellow flower plants in the F2 generation must be 25%.

(c) The expected ratio of the genotypes WW and Ww in the F2 progeny will be 1:2.