In watermelons, bitter fruit (B) is dominant over sweet fruit (b), and yellow spots(S) are dominant over no spots (s). A homozygous plant that has bitter fruit and yellow spots is crossed with a homozygous plant that has sweet fruit and no spots. The F1 are intercrossed to produce F2.
What will be the phenotypic ratios in F2?
I don't understand how to choose the possible gametes for the f2 generation to set up my punnett square. Please help!

Question

In watermelons, bitter fruit (B) is dominant over sweet fruit (b), and yellow spots(S) are dominant over no spots (s). A homozygous plant that has bitter fruit and yellow spots is crossed with a homozygous plant that has sweet fruit and no spots. The F1 are intercrossed to produce F2.
What will be the phenotypic ratios in F2?
I don't understand how to choose the possible gametes for the f2 generation to set up my punnett square. Please help!

anonymous · Answer

P - BBSS x bbss
F1 - BbSs x BbSs
a. 9 (bitter w/ spots): 3 (bitter w/ no spots) : 3 (sweet w/ spots) : 1 (sweet w/ no spots)
b. 100% bitter with spots . BBSS - 1/4; BbSs - 1/4; BBSs - 1/4; BbSS- 1/4
c. BbSs - Bitter w/ spots - 1/4 ; Bbss - bitter w/ no spots - 1/4 ; bbSs - sweet w/ spots - 1/4 ; bbss - sweet with no spots - 1/4