Advanced screening and breeding approaches for heat tolerance in wheat

Food and nutritional security will be decline by consequent changes in climate condition. Global warming is predicted the frequency and severity of heat stress. Global climate change risks are expected that global mean temperature increase at 0.3% per decade. Wheat is very sensitive to heat stress, it is a complex function of heat intensity, duration of exposure, rate of rise in temperature. It is the most widely cultivated cereal crop in the world so play an important role in food security. Wheat have different responses at different developmental stages to heat stress, during vegetative, reproductive and grain filling stage. For instance, inhibit germination, seedling subjected to short term heat stress showed reduction in dry mass, shoot and root length. Physiological responses waters relations, accumulation of compatible osmolytes, heat stress often leads to the generation of reactive oxygen species (ROS). Heat tolerance- ability of some genotypes to better perform than others when their internal temperatures are comparable and in the realm of heat stress. Plants also implement various mechanisms against HS such as ion transport, osmoprotectants, maintenance of membrane stability, scavenging of ROS. Screening methodologies for heat tolerance that are cell membrane thermo-stability test, chlorophyll content, canopy temperature depression (CTD). Breeding strategy for heat tolerance crops, conventional breeding, strategies employing traditional breeding protocols to develop heat tolerant crop. Genetic improvement for heat-stress tolerance, these responses accommodate short-term reaction and tolerance to specific stresses, molecular marker technology and genetic transformation, have resulted in genetic characterization and development of plants. The application of quantitative trait locus (QTL) mapping has contributed to a better understanding of the genetic relationship among tolerances to different stresses. Biotcnological approaches to study and improve plant stress tolerance include MAS and genetic transformation.