ABSTRACT
Nowadays, the climate is changing globally. High temperature affects cellular membrane stability, chlorophyll fluorescence, photosynthesis, and antioxidant enzymes activities in plants. Cotton is susceptible to high temperature during the reproductive growth stage, particularly during the flowering and boll formation periods. Reduced yields associated with heat stress are common in upland cotton areas and have been partially attributed to reproductive dysplasia, including increased fruit shedding, reduced pollen viability, fertilization efficiency, and boll size and seed number. Hence, it is imperative to explore the cotton germplasm to identify heat-tolerant genotypes. The rapid developments in modern biotechnology, including molecular marker-assisted selection and next-generation sequencing technologies, have facilitated cotton breeding. This chapter begins with an introduction to the cause of heat stress in cotton and the underlying theory of heat tolerance in cotton. Then, breeding methods based on marker-assisted selection and even genomic selection, together with how to explore elite alleles of heat tolerance from wild species or mutated materials are summarized. Finally, new prospects of cotton breeding based on the above-mentioned methods are presented and discussed.
