ABSTRACT

Improvement of host plant resistance to diseases caused by soilborne microbial plant pathogens has immense practical importance. Host resistance indicates the magnitude or capacity of a plant species or cultivar to reduce activity or harmful effects of a microbial pathogen. Evaluation of germplasm collections and wild relatives of crop plant species, for their level of resistance to the pathogen(s) concerned, is the basic step for the development of cultivars with built-in resistance and this is the most economical and environmentally safe approach of crop disease management. Assessment of pathogen populations in infected plants has been carried out to determine its reliability as a measure of host resistance to crop diseases. Various mechanisms may be in place in plants to effectively meet the challenges posed by bacterial plant pathogens, which have different levels of virulence, whereas plants are endowed with resistance genes for protecting themselves.