Role of molecular markers in improving abiotic stress tolerance in agricultural crops

Molecular markers are one of the expandable inventions in agricultural science. After decades of their introduction, these still are an integral part of crop genotyping and crop improvement. The present scenario offers to choose from different molecular marker types based on their principle, methodologies and extent of applications. Several markers have been used to identify and map abiotic stress related genes and quantitative trait loci (QTL) onto the chromosomes of different crops. The genetic mapping of these identified genetic elements by using different markers provides the scope of selective breeding in the agricultural crops to tackle abiotic stresses. Moreover, recent progress achieved in genetics, molecular breeding and genomic selection has facilitated a comprehensive understanding of the molecular markers and unlocked new insights into marker-assisted breeding. The advent of new technologies like association mapping (AM) and genome-wide association studies has unveiled the high-throughput application of molecular markers. In this review, a focused representation of the use of different molecular markers in the identification of tolerant crop genotypes and associated genes/QTLs against major abiotic stresses, including salinity, drought and temperature has been provided. Additionally, the application of molecular markers in AM and AM-based breeding of some important agricultural crops has been discussed.