In sweet peas, purple flower color and oblong pollen grains are dominant, with the recessives being red flower color and spherical pollen grains.When a homozygous purple, oblong plant is crossed with a homozygous red, spherical plant, the F₁ generation consists entirely of purple, oblong plants.When an F₁ plant is crossed with a homozygous red, spherical plant, the offspring are produced in a ratio of 7 purple, oblong to 1 purple, spherical to 1 red, oblong to 7 red, spherical.Which of the following is the only plausible explanation for such results?

Question

Quizplus · Accepted Answer

The results suggest that the purple and oblong traits are linked on one chromosome, while the red and spherical traits are linked on another chromosome. This is because the F₁ plant must have received both dominant traits on the same chromosome from the homozygous parent, resulting in a homozygous dominant plant, while the offspring from the second cross show a 9:7 ratio, which is indicative of two linked traits. Fertilizer, bad sex cells, and plant resentment are not plausible explanations for the results.

In Sweet Peas, Purple Flower Color and Oblong Pollen Grains