In cucumbers, orange fruit color (R) is dominant over cream fruit color (r). A cucumber plant homozygous for orange fruit is crossed with a plant homozygous for cream fruit. The F1 are intercrossed (F1 individuals crossed with F1 individuals) to produce the F2.

a. Give the genotypes and phenotypes of the parents, the F1, and the F2.
b. Give the genotypes and phenotypes of the offspring of a backcross between the F1 and the orange-fruited parent.
c. Give the genotypes and phenotypes of a backcross be- tween the F1 and the cream-fruited parent

Respuesta :

Answer:

a)

Homozygous for orange will be RR

Homozygous for cream will be rr

On crossing the two cucumbers, the genotype for all the off springs in the  F1 generation will be Rr

Therefore all the off springs in the F1 generation will be phenotypically Orange since R is dominant over r

When the F1 are crossed. The genotype for the off springs will b;  RR, Rr, Rr and rr. Therefore 3 orange and 1 cream

b)Back cross with orange(RR×Rr)

Genotype: RR, RR,Rr, Rr

Phenotype;All orange

c)Back cross with cream(Rr×rr)

Genotype: Rr, Rr, rr, rr

Phenotype: 2 orange and 2 cream