Determine the....?

In snapdragon, red flower color (R) is incompletely dominant to white (r); the R/r heterozygotes are pink. A red flowered snapdragon is crossed with a white-flowered one. Determine the flower color of (a) the F1; (b) the F2;(c) the progeny of a cross of the F1 to the red parent; (d) the progeny of cross of the F1 to white parent .

Determine the....?
Red crossed with white: RR x rr.


All the F1 are Rr pink because each gets R from one parent and r from the other parent.





b. The F2 is produced by crossing two of the F1s.


Rr x Rr


Gametes: R and r from one parent on left side of Punnett square; R and r from other parent on top of Punnett square.


First row of square: RR and Rr


Second row of square: rR and rr


Phenotypes of F2: 1 red: 2 pink: 1 white





c. Cross F1 pink with red parent


Rr x RR


Gametes: R and r; R and R


Offspring: RR, RR, rR, rR 1 red: 1 pink





d. Cross F1 pink with white parent


Rr x rr


Gametes: R and r; r and r


Offspring: Rr, Rr, rr, rr 1 pink: 1 white
Reply:Ok...just to tell you my punnett square don't always come out like they are supposed to...just know that on the top is 1 parent and down the far left is parent 2.





So Red flower is RR


Pink is Rr


and white is rr


This makes it easy when loking at the offspring as there are 3 genotypes and 3 phenotpyes (unlike complete dominance where you have 3 genotypes and only 2 phenotpyes)





crossing RR x rr


R R


r Rr Rr





r Rr Rr


All F1 flowers will be Rr (pink)





so the next cross is between these F1 flowers (Rr)..or at least I think you need that.


Rr x Rr





R r





R RR Rr





r Rr rr





You will have 1 red: 2 pink : 1 white. The classic 1:2:1 ratio





F1 (Rr) x RR (red parent)





R r





R RR Rr





R RR Rr





You will have 2 red: 2 pink or 50% red:50% pink flowers





F1 (Rr) x white parent (rr)





R r


r Rr rr





r Rr rr





you will get 50% pink: 50% white or 2 pink: 2 white.





Hope this helps