ABSTRACT
Biotechnology for Improvement of Crop Disease Resistance Use of genetically resistant cultivars for management of crop disease is known to be the most economical method. However, the lack of durability of resistance for longer periods has been the major drawback because of the selection pressure exerted on the microbial pathogens which may, sooner or later, adapt themselves to the newly introduced resistance genes and produce new strains. Furthermore, the unavailability of dependable sources of resistance to many economically important diseases such as wheat take-all disease caused by Gaeumannomyces graminis var. tritici and rice sheath blight disease caused by Rhizoctonia solani (Thanatephorus cucumeris) is another formidable obstacle to always adopting this strategy for disease management (Chapter 11). The limitations of other principal strategies of crop disease management such as adoption of suitable cultural practices (Chapter 9) and application of chemicals (Chapter 14) have necessitated the search for alternative solutions to overcome the problems posed by microbial plant pathogens that cannot be tackled effectively by conventional crop disease management methods.
