Improving tolerance of cotton (Gossypium hirsutum L.) to drought and heat stress.

Abstract Drought and heat stress are burning issues for agriculture in the climate change scenario due to which lower yield and production of crops have been projected. In this situation, sustainable production of food and fiber crops is a challenge. Cotton (Gossypium hirsutum L.) is a major cash crop of the world including Pakistan, and its growth and yield are highly influenced by drought and heat stress. Development of drought and heat stress tolerant genotype is the most sustainable way to cope with this stress. In this review, different tolerance mechanisms of the cotton plant against heat and drought stress are discussed. These tolerance mechanisms include morphological, physiological, biochemical, and genetic adaptations of cotton plant to the external stress. Moreover, different strategies to improve the tolerance of cotton against heat and drought stress have also been discussed. As both stresses complement each other in most of the cases and some mechanisms are the same for both stresses, therefore, both are discussed together. Prospects and challenges have also been discussed.