Biology: Concepts and Investigations 2nd Edition by Mariëlle Hoefnagels

Exercise 64

In an attempt to breed winter barley that is resistant to barley mild mosaic virus, agricultural researchers cross a susceptible domesticated strain with a resistant wild strain. The F1 plants are all susceptible, but when the F1 plants are crossed with each other, some of the F2 individuals are resistant. Is the resistance allele recessive or dominant? How do you know?