**4. Conclusion and future perspectives**

In the wake of global warming and climate change, abiotic stresses like salinity is a major constrain to agriculture and allied sector which affects sustainable food and nutrition security. During last decades considerable efforts have been made to decipher mechanism of stress resistance and metabolic processes against various environmental factors affecting plant growth and yield potential (**Figure 3**). The degree of salt stress and plant growth stage are mainly responsible for foreseeing how plants defend and respond to prevailing stress conditions. In terms of drought, stomata close progressively along with a parallel reduction in water-use efficiency and net photosynthetic activity. Under drought conditions, lower stomatal conductivity and moisture use-efficiency leads to the impaired photosynthetic potential and overall growth in plants. In addition to several aspects, changes of plant pigments were found to be closely related to salinity tolerance in crops. In plants, self-defense mechanism operated at cellular level in leaf is triggered frequently to protect entire solar energy trapping system existing in the form of photosynthetic machinery from permanent damage. Removal of reactive-oxygen species through multiple enzymatic and non-enzymatic antioxidant defense pathways, cellular transportation and membrane stability, expression of underlying genes networks, and biosynthesis of array of defensins are key mechanisms of salinity tolerance.

Several plant genetic and genomic resources have been generated to address the abiotic stresses by different scientific groups under independent and coordinated research programs globally. With the use of conventional plant breeding approaches, multiple crop varieties, elite cultivars, promising lines and germplasm collections and gene bank accessions have been developed and preserved for cereal crop species. To support the traditional phenotypic selection-based breeding, advanced highthroughput phenotypic tools have also been devised and being utilized in phenotyping of various phenotypic traits manifested under stress conditions. Similarly, with advancement and availability of the next-generation sequencing technology at

affordable cost, has paved the way to develop high-throughput genotyping platforms that used in whole-genome sequencing. The NGS-based genomic tools including SNP markers, genome maps, genome-wide QTLs and MTAs and gene networks underlying abiotic stress resistance have been deciphered and implemented in crop improvement programs to achieve higher genetic gains. Despite of technological advancements and resource mobility, usually a significant gap in terms of mutual cooperation and liaising needed in lab to land technology transfer have been witnessed at both institutional and scientific levels. Moreover, the potential of untapped alleles occurring in wild genetic stocks and genomic advancement are yet to be realized adequately in plant breeding.
