Principles and Practices of Mapping QTLs in Plants

The major challenge in current biology is to understand the genetic basis of variation for quantitative traits. The genetic variation of a quantitative trait is controlled by the collective effects of numerous genes, known as quantitative trait loci (QTLs). Identification of QTLs of agronomic importance and its utilization in a crop improvement requires mapping of these QTLs in the genome of crop species using molecular markers. Mapping quantitative trait loci (QTL) for complex traits has become a routine tool in functional genomic research. This chapter will focus on the basic concepts, prerequisites of QTL mapping, approaches for understanding the function of a gene, a brief description of existing methodologies for QTL mapping and their advantages and disadvantages.