High-temperature Tolerance in Cotton

Cotton is mostly grown in tropical and subtropical countries for its fiber and oil. Heat stress significantly reduces its productivity. Cotton is affected by high-temperature stress at every growth and development stage. However, the reproductive stage is considered the most susceptible one. Heat stress reduces pollen viability, fertilization, and boll retention, resulting in significant yield losses. It also alters membrane integrity, hinders enzyme processes, and produces an excessive quantity of reactive oxygen species. These causes oxidative stress and metabolic imbalances at cellular levels. Conventional breeding techniques have been used to overcome these challenges by utilizing the genetic diversity within available cotton germplasm to breed heat-tolerant cultivars. Novel genomic tools also offer promising solutions for its improvement through molecular breeding. Keeping in view the importance of cotton and its productivity challenges due to heat stress, this chapter provides the basics of understanding about physiological and molecular mechanisms of heat stress in cotton and also highlights some strategies to enhance its resilience to ensure optimal yield with quality fibers.