Trait Mapping, Marker-Assisted Selection, and Introgression Breeding in Pearl Millet

Pearl millet (Pennisetum glaucum (l.) R. Br.) is a staple food crop in the arid and semi-arid tropics that is gaining importance as a climate-resilient crop. Polygenes control important pearl millet traits, and the improvement of such traits requires the identification of the genomic regions underlying them. The genomic regions associated with the trait of interest are identified using molecular markers through quantitative trait locus (QTL) mapping and association studies. The results obtained from mapping studies are further improved by validation through fine mapping, gene expression studies, and using alternate mapping populations. The identified genomic regions are utilized in marker-assisted approaches such as marker-assisted backcross breeding, marker-assisted gene pyramiding, and marker-assisted recurrent selections. The marker-aided approaches can be integrated with other techniques, such as speed breeding and doubled haploid technology, to increase efficiency and reduce the breeding cycle time. Basic knowledge about the prerequisites for marker-assisted breeding, establishing marker-trait associations, QTL validation, and marker-assisted breeding approaches are reviewed.