S. Suresh

Yield and quality are central to sustainable crop production. Due to biotic stress, yield loss upto 52 per cent. Chemical control of insect and disease is not feasible for environments and economical not viable. Host plant resistance is the only safe, economical, and environment friendly way for the absolute control of this devastating pest and disease. Historically, long-term cultivation of varieties carrying single resistance gene has resulted in a significant shift in pathogen or insect race frequency and consequent breakdown of resistance. One tangible solution to resistance breakdown is pyramiding of multiple resistance genes in the back-ground of modern high yielding varieties. Gene pyramiding aims to assemble multiple desirable genes into a single genotype. The main use of gene pyramiding is to improve an existing elite cultivar through introgression of a few genes of large effects from other sources, since the presence of the target genes has to be monitored by phenotyping, which is only effective for major genes. Gene pyramiding is difficult to achieve using conventional breeding alone because of linkage with some undesirable traits that is very difficult to break even after repeated backcrossing. .