2 If you found a W warhawkiensis plant with large purple flo

2. If you found a W. warhawkiensis plant with large purple flowers, how could you determine its genotype? Describe the cross that you would use and all of the possible outcomes (eg. ‘If the genotype is _/_; _/_, then the outcome of the cross will be ….’.).

Cross:

Possible outcomes:

Solution

Let us assume that the flower is true breeding, with different genes for flower size and flower colour

Let us denote the alleles as follows -

Large flowers - L
Small flowers - l

Purple flowers - P
Colourless flowers - p

Case : The parent flower is homozygous.

In this case, the flower will have the genotype PPLL

Cross 1: Dominant parent with Recessive parent
Genotype of dominant parent - PPLL
Genotype of recessive parent - ppll

PPLL X ppll

Outcome: All plants will have the genotype as PpLl, which will have the phenotype as Purple and Large flowers.

Cross 2: The F1 progeny is crossed with another F1 ( selfing)

In this case, the cross would be PpLl X PpLl

Outcome: The following phenotypes would be obtained -

Purple and Large - 9
Purple and Small - 3
Colourless and Large - 3
Colourless and Small - 1

Therefore, the phenotypic ratio would be 9:3:3:1