Agronomic and genetic approaches for enhancing tolerance to heat stress in rice: a review

Rice is an important cereal crop worldwide that serves as a dietary component for half of the world’s population. Climate change, especially global warming is a rising threat to crop production and food security. Therefore, enhancing rice growth and yield is a crucial challenge in stress-prone environments. Frequent episodes of heat stress threaten rice production all over the world. Breeders and agronomists undertake several techniques to ameliorate the adverse effects of heat stress to safeguard global rice production. The selection of suitable sowing time application of plant hormones, osmoprotectants and utilization of appropriate fertilizers and signaling molecules are essential agronomic practices to mitigate the adverse effects of heat stress on rice. Likewise, developing genotypes with improved morphological, biochemical, and genetic attributes is feasible and practical way to respond to this challenge. The creation of more genetic recombinants and the identification of traits responsible for heat tolerance could allow the selection of early-flowering cultivars with resistance to heat stress. This review details the integration of several agronomic, conventional breeding, and molecular approaches like hybridization, pure line selection, master-assisted-selection (MAS), transgenic breeding and CRRISPR/Cas9 that promise rapid and efficient development and selection of heat-tolerant rice genotypes. Such information’s could be used to determine the future research directions for rice breeders and other researchers working to improve the heat tolerance in rice.