Marker-assisted breeding for stress resistance in crop plants

Abstract

Molecular markers have extensively been used for tagging and mapping of genes and QTLs conferring resistance to biotic and abiotic stresses. These tools have also been used for screening of germplasms, fingerprinting, and marker-assisted breeding in crop systems. This chapter presents an overview on the basic concepts of molecular mapping and marker-assisted breeding and its most widely used applications in crop improvement programs, viz., marker-assisted backcross breeding, gene introgression, gene pyramiding, and marker-assisted selection at an early generation, with emphasis on stress-related traits and examples from several crops. We have also discussed some quantitative aspects of marker-based introgression, backcross breeding, and gene pyramiding programs. We have also added a note on breeding by design and genomic selection as tools for future breeding endeavors aiming at introgression of stress resistance into high-yielding cultivars. Harnessing the full potential of marker-aided breeding for improvement of stress resistance in crop systems will require a multidisciplinary approach and integrated knowledge of the molecular and physiological processes influencing the stress-related traits. Hence, marker-aided breeding for stress resistance in the post-genomic era poses great challenge for molecular breeders to realize the target objectives.