Question

In peas the flower color and pollen length genes are very close together on the same chromosome. Purple flowers (P are dominant to white (p), and long pollen (L) is dominant to short pollen (l). A true breeding variety of peas with purple flowers and short pollen is crossed to a true breeding variety with white flowers and long pollen. The F1 plants are then self-crossed to produce an F2 generation.
Required:
a. What is the genotype and phenotype of the F1 generation?
b. What proportion of the F2 will have purple flowers with long pollen?
c. What proportion will have white flowers and short pollen?

Answer 1

Answer:

Explanation:

Purple flowers (P are dominant to white (p), and long pollen (L) is dominant to short pollen (l).

A true breeding variety of peas with purple flowers and short pollen is crossed to a true breeding variety with white flowers and long pollen.

Parent genotype           PPll   x   ppLL

F1 genotype will be           PpLl

self crossing of F1     PpLl   x   PpLl

b. What proportion of the F2 will have purple flowers with long pollen?

  Pp x Pp = 3/4 purple flowers, 1/4 white flowers

  Ll x Ll = 3/4 long pollen, 1/4 short pollen

Thus answer is 3/4 x 3/4 = 9/16 purple flowers with long pollen

c. What proportion will have white flowers and short pollen?

thus, answer is 1/4 white flowers x 1/4 short pollen = 1/16.