Question

42) When yellow-seeded and green-seeded pea plants are crossed, all the offspring are yellow-seeded. When the F1 yellow-seeded plants are crossed to green-seeded plants, what is the hypothesized genetic ratio

Answer 1

See the answer below

Step-by-step explanation:

From the illustration, the yellow color trait is dominant over the green trait.

Assuming that yellow seededness is represented by the allele Y and green seededness by the alleles y. Y is dominant over y, hence a yellow seeded plant would be either YY or Yy while a green seeded plant would be yy.

For a cross between a yellow seeded plant and a green seeded plant to yield all yellow seeded offspring, it means that the parents are YY and yy.

(yellow)YY x (green) yy

F1 progeny: All Yy (yellow)

Now, Yy is crossed with green-seeded plant, yy.

Yy x yy

Yy Yy yy yy

Hypothesized Genotypic ratio

Yy = 1/2

yy = 1/2

Hypothesized Phenotypic ratio

Yellow seeded = 1/2

green seeded = 1/2