Molecular Markers and Marker-Assisted Selection in Crop Plants

Molecular markers have revolutionized the plant biotechnology and genetic studies because of their versatility. These markers include biochemical constituents like secondary metabolites and macromolecules, viz., proteins and deoxyribonucleic acids (DNA). The secondary metabolites are specific to particular plants species that produce them; therefore, the technique has a restricted application. Also, these are influenced by the environmental factors and/or management practices. The molecular markers based on the DNA polymorphism, however, are more suitable and ubiquitous to most of the plant species. These are stable and could not be influenced by environmental factors and/or management practices. Among the other applications of DNA markers, the most promising for plant breeding is marker-assisted selection (MAS). The application requires the markers to be linked with genes of economic significance, cost-effective, and applicable to large number of samples as well as a wide range of crosses in a breeding program. In this chapter, we review the literature about molecular markers, their advantages, disadvantages, and the applications of these markers in marker-assisted selection (MAS) in crop plants.