Genetic mapping refers to the determination of distance and order of genes/QTL on the chromosome. The conventional linkage analysis has been used to this purpose leading to publication of first genetic map of 6 sexlinked genes on a fruit fly chromosome. In plants, genetic linkage maps have been developed for major gene controlling the qualitative traits in several crops. However, the possibility of locating the QTL controlling the quantitative traits has also been investigated earlier using morphological traits as genetic markers. However, the advent of molecular markers has sped up the development of dense molecular maps and QTL analysis in crop plants. This led to the identification of QTL for desirable traits of agronomic importance. In this chapter, we discussed the basic principles of molecular genetic mapping and QTL analysis in plants.
Keywords: gene, genetic mapping, linkage, LOD scores, mapping population, QTL analysis.