Understanding Heat and Drought Stress Adaptation Mechanisms in Wheat: A Combined Approach

Abstract

Drought and heat are the key environmental stressors significantly decreasing wheat productivity (86 and 69%, respectively) and weakening food security in the major wheat growing regions worldwide. Wheat crops have regularly experienced combined (Heat+Drought) stress in the field and the joint effects are more detrimental to wheat growth than the effects of each stress separately.Drought and heat stress have shown synergistic, antagonistic, or hypo-additive impacts on growth, grain filling, and yield parameters when combined. In order to escape and/or tolerate these unfavorable environmental conditions, wheat has developed advancedresponses at various levels. This review explores how physiological, morphological, biochemical and molecular traits work together to provide tolerance to coupled stresses. Importance of specific traits such as, canopy temperature, assimilate partitioning and water use efficiency along with reproductive traitswhich provide tolerance against these combined stressors has also been explained. This review also highlighted the potential of altered agronomic practices, application of micronutrients, biopriming of seeds (endophytes) against abiotic stresses. Further emphasize has been given to promising novel technologies like, genome editing (CRISPR),identification of novel QTL's and alleles to improve both heat and drought tolerance for sustainable wheat production.