Mendel crossed Y/Y;R/R (yellow wrinkled)peas with y/y;r/r (green smooth)peas and selfed the F₁ to obtain an F₂.What proportion of the F₂ individuals were pure-breeding?

Question

Quizplus · Accepted Answer

When Mendel crossed Y/Y;R/R with y/y;r/r, the F1 generation all had Yy;Rr genotype, which were all yellow and round. When he selfed the F₁, he obtained F₂ with genotypes YYRR, YYRr, YyRR, YyRr, YYrr, Yyrr, yypure-breeding for green and rr pure-breeding for wrinkled. Out of these, only YYRR and yypure-breeding are pure-breeding, so the proportion of pure-breeding individuals is 1/4 or 25%. Therefore, the correct answer is C.

Mendel Crossed Y/Y;R/R (Yellow Wrinkled)peas with Y/y;r/r (Green Smooth)peas and Selfed