Quick response to pathogens by plants or animals has been graded as hypersensitive response. For durable resistance this type of response is not desirable, because this is not reliable. Then why this type of response is being exploited by breeders to develop high yielding disease resistant varieties?
Muhammad Aslam Khan There are so many different physiological and genetic mechanisms leading to lower disease incidence/development that it is difficult to place them under a few names offered for the model cases. For tomato, race-specific HR provided only 30% of resistance to bacterial leaf spot disease in the field. But, for researcher, it is easy to work with monogenic HR (germplasm screening at early stage, race typing, molecular markers, QTLs, etc.!). For breeders, HR to one pathogen is often linked to strong plant reaction against many other factors (pathogens), so it can be a complex trait.
