ABSTRACT
This chapter deals with the basic principles, requirements, and advantages and disadvantages of the most widely used molecular markers. In plant breeding, restriction fragment length polymorphism was the first molecular marker technique developed and used in marker assisted selection. In plant breeding, enzymes such as isozymes are used as biochemical markers. Isozymes are expressed in the plant cells, and are extracted and run on denaturing electrophoresis gels. In the selective mating of individuals of a population or breeding, desired morphological, physiological, or genetic traits such as appearance, yield, and disease resistance are either isolated or combined. The duration of breeding programmes have been shortened from years to months to weeks, or even eliminated because of biochemical and molecular techniques. When molecular markers were used in conventional breeding techniques, the accuracy of crosses improved and breeders were able to produce strains with combined traits.
