The terms horizontal resistance and vertical resistance were first used by

The terms horizontal resistance and vertical resistance were first used by Van Der Plank in 1963.
The term vertical resistance, used commonly in the context of plant selection, was first used by J. E. Vanderplank to describe single-gene resistance. This contrasted with the term horizontal resistance which was used to describe many-gene resistance.
Genetic resistance that is effective at preventing successful attack only by certain races of a pathogen is called specific or vertical resistance, whereas resistance that is effective at preventing successful attack by all races of a pathogen is called general or horizontal resistance.