Abstract

Abiotic stress negatively influences survival, biomass production and crop yield. Being multigenic as well as a quantitative trait, it is a challenge to understand the molecular basis of abiotic stress tolerance and to manipulate it as compared to biotic stresses. Abiotic stresses including drought are serious threats to the sustainability of crop yields accounting for more crop productivity losses than any other factor in rainfed agriculture. Success in breeding for better adapted varieties to abiotic stresses depend upon the concerted efforts by various research domains including plant and cell physiology, molecular biology, genetics, and breeding. Use of modern molecular biology tools for elucidating the control mechanisms of abiotic stress tolerance, and for engineering stress tolerant crops is based on the expression of specific stress-related genes. Plant responses to water deficit can be analysed by systematically identifying genes that relate to drought tolerance followed by analysis to the cellular, biochemical and molecular basis of the gene (traits). Mechanism of drought tolerance and expression of these drought resistance genes in high yielding varieties will help to improve the drought condition. The genes conferring drought resistance provide foundation for scientific improvement of the crop’s productivity under arid conditions and contribute to improvement and stabilization of cotton yield and farmers' income. Stress-induced gene expressions are of genes encoding proteins with known enzymatic or structural functions, proteins with as yet unknown functions, and regulatory proteins.

Key words: Abiotic stress, stress induced genes, regulatory proteins, transgenics.