Question

Consider a cross to investigate the pea pod texture trait, involving constricted or inflated pods. Mendel found that the traits behave according to a dominant/recessive pattern in which inflated pods were dominant. If you performed this cross and obtained 650 inflated-pod plants in the F2 generation, approximately how many constricted-pod plants would you expect to have?

a. 600

b. 165

c. 217

d. 468

Short answer

The correct answer is (c). 217

Step-by-step solution

Introduction

Hybridization in plants was performed by Gregor Mendel for the first time. He mated two individual plants, which were true-breeding and had different traits. Traits are the variations seen in the phenotype, or appearance of heritable characteristics.

Traits can either be dominant or recessive. The traits which are inherited in an unchanged manner in hybridization are dominant. Dominant traits are 100 percent expressed in F₁ generation and 75 percent in F₂ generation.

Explanation

If, in a cross between constricted and inflated pod plants of the 1000 F₂ offspring, 650 inflated pod plants were obtained in the F₂ generation. This indicates that inflated pod is a dominant trait.

Since, recessive trait is expressed 25 percent in F₂ generation, the number of constricted pod plants cannot be 600, 468 or 165. Hence, option (c) is the correct answer.