ABSTRACT
The world population is increasing day by day along with a decrease in total cultivated area. Climatic change and evolution of new pest and disease biotypes have also raised serious challenges in front of breeders to not only increase the production and productivity but at the same time enhance resistance to biotic and abiotic stresses as well. Breeding for plant resistance to stress is the most competent and inexpensive way of maintaining and enhancing the yield of economic product obtained from plants. Tremendous advances have been made to understand the physiological and molecular mechanisms controlling resistance to stress. With the advent of molecular marker technology, the dissection of complex and polygenically inherited traits has become possible, thereby helping in the detection of numerous stress resistance genes linked to molecular markers. Genetic mapping of 138quantitative traits loci (QTLs) and certain major genes affecting economically important traits have led to the amalgamation of biotechnology and conventional breeding procedures. The information obtained in the form of map position of economically important traits and linked molecular markers can be exploited by means of selection of traits using marker-assisted selection (MAS). MAS involves the selection of the desired individuals on the basis of DNA marker patterns rather than, or in addition to, the phenotypic values for the trait. When used appropriately, MAS is a tool that could help breeders select more efficiently, thereby increasing both the reliability and the speed of selection. Along with other advantages MAS also helps in performing selection at an early stage of growth.
