Breeding for Abiotic Stress Adaptation

Abstract

Abiotic stress is defined as the negative impact of non-living factors on the living organisms in a specific environment. The literal meaning of the word “stress” is coercion, that is, force in one direction. In Physics, stress is tension produced within a body by the action of an external force. Biologically, stress is a significant deviation from ideal conditions. Stress prevents plants from expressing their full genetic potential for growth, development and reproduction. Stress is a stimulus that surpasses the usual range of homeostatic regulation (homeostasis is stability or balance of the plant body – it is the body’s attempt to maintain a constant internal environment) in any living being. Abiotic stresses (water deficit, high temperature, low temperature and high salinity) pose a serious threat to the food security worldwide. It poses a negative influence on the plant’s survival and can reduce biomass and yield by up to 50–70%. Any stress above the threshold can activate a cascade of responses at physiological, biochemical, morphological and molecular levels. This cascade of responses helps to withstand the stress. Stress tolerance is a quantitative trait with complex gene regulations. Molecular mechanisms and various complex signalling pathways govern such gene regulations, and such a process involves activation and deactivation of stress responses.