Physiological Responses, Molecular Basis, and Integrated Regulation of Heat Tolerance in Soybean

Global warming has led to frequent occurrences of extreme heat, posing a huge threat to soybean (Glycine max L.) yield. As a major source of plant protein and oil, soybean is particularly sensitive to heat stress during its growth and development, especially in critical stages such as flowering and seed filling. Heat tolerance in crops is a complex trait governed by polygenic networks and environmental interactions; although existing studies have identified several heat-tolerance-related genes, the molecular regulatory networks regulating crop responses to heat stress remain elusive. This review synthesizes recent advances in soybean heat tolerance research, with a particular emphasis on physiological responses and molecular regulatory mechanisms under heat stress. We further evaluate the potential of modern technologies, including gene editing, marker-assisted selection, and pan-genomics, for the precise improvement of heat tolerance in soybean. Additionally, we outline sustainable agronomic practices and field management strategies to mitigate heat stress. The development of heat-tolerant soybean varieties depends not only on the identification of superior alleles but also requires a shift from gene-centric genetic improvement toward a system-wide solution that integrates "Genotype × Environment × Management".