beckygardener said:Also, I do not understand what it means between "horizontal resistance" and "vertical resistance". Can someone clue me in about this in layman's terms?
Vertical resistance means resistance is related to a single gene and is specific to an individual race of the pathogen (meaning a plant cultivar may be susceptible to one race but not to another). Horizontal resistance involves several genes and can protect from all races of a pathogen. Horizontal resistance is less prone to a breakdown in resistance than vertical resistance because with the latter there is only one resistance gene for the pathogen to overcome. With horizontal resistance you can still see some disease on the plant but to a minimal extent.
That's the theory anyway, and this is probably an oversimplification (for both our benefits)!
@admmad would be able to explain better.
