Question

Molly wants to breed a variety of roses that are light pink with no thorns. She is starting with two true-breeding rose plants with the following phenotypes: Parent 1 - white flowers (pp) and thorns (TT) Parent 2 - dark pink flowers (PP) and no thorns (tt) The F1 generation has light pink flowers, but still has thorns. So, flower color must be incompletely dominant, but thorns show complete dominance. Which plant should she cross her F1s with t get the highest number of plants with the correct phenotype? A. Parent 1 Space to work provided on B. Parent 2 next slide C. Other F1s D. Parent 1 &2 both give the same best results E. Parent 2 & the F1s both give the same best results

Answer 1

What Molly has done:

Parents ppTT X PPtt

Gametes pT Pt

F1- PpTt light pink flowers with thorns

F1 if crossed with parent 1:

PpTt X ppTT

Gametes PT Pt pT pt and pT

F2 offsprings:

PpTT light pink, thorns

PpTt light pink, thorns

ppTT white, thorns

ppTt white, thorns

F1 if crossed with parent 2:

PpTt X PPtt

Gametes PT Pt pT pt and Pt

Offsprings of F2 gen:

PPTt dark pink, with thorns

PPtt dark pink, thornless

PpTt light pink, with thorns

Pptt light pink, thornless

Cross with parent 2 is giving better results thus, option B should be opted as answer.