Resistance: the phenotype

Resistance is a phenotype produced by the interactions of host genes for resistance and pathogen avirulence in an environment that is conducive for disease development. Plants develop a range of symptoms in response to pathogen attack. There is a continuum of resistance outcomes, from immunity to mildly resistant. An innate immune system (nonhost) resistance protects plants from most pathogens. When the innate immune system is breached there are multiple and different approaches the plant breeder can exploit to develop a resistant cultivar. A resistant plant is always from the point of view of the plant breeder, and subsequently the grower.