**4.2 DNA technology**

Previously, it would require about 7–10 years to transfer a target trait from a species to an adapted cultivar. The conventional process requires, handling a large number of progenies and several cycles of field evaluation. However, with molecular biology, a gene can be transferred in a single experiment, and within 5–6 years the new cultivar could exhibit a stable gene expression [136]. Presently, advances in plant molecular biology have provided processes and platforms through which the genetic architecture of traits can be well understood, manipulated, and transferred from different backgrounds [136, 137]. In addition, through DNA technology, gene sequences and functions can be accessed. Similarly, specific region (s) on the chromosome can be identified, molecular markers can be developed and genetic maps can be constructed, among many other possibilities. Genetic manipulation using physical, chemical, and biological mutagenesis presents added advantages with an enormous contribution to crop improvement. Among the widely used DNA technology reported in crop improvement programs are Genome-Wide Association Study (GWAS), Quantitative Trait Loci (QTL) Mapping, and Genome Editing.
