Unraveling Advances in Rice Male Sterility Systems: From Genetic Basis to Hybrid Breeding Innovation

Heterosis is a landmark innovation in modern agriculture, which has been widely exploited to boost crop productivity. As a staple food for over half of the global population, rice depends heavily on heterosis for yield improvement. Notably, hybrid rice has made remarkable contributions to global food security over the past several decades. Male sterility serves as the fundamental basis for efficient hybrid rice breeding, with cytoplasmic male sterility (CMS) and genic male sterility (GMS) as the core systems employed in practical production. CMS, induced by mitochondrial genes, can be restored to fertility by nuclear restorer genes, thereby forming the essential genetic basis for the three-line hybrid rice system. GMS, mainly regulated by the nuclear genome, includes dominant and recessive nuclear sterility. Specifically, recessive environment-sensitive genic male sterility (EGMS) has facilitated the development of the two-line hybrid rice system for commercial hybrid seed production. The third-generation hybrid rice technology (TGHRT) is a transgenic approach developed for propagating stable recessive GMS lines. This review comprehensively summarizes the latest advances in rice male sterility systems, focusing on their genetic classification, origin, and molecular mechanisms. It further analyzes their application status, inherent limitations, future research directions, and development trends in hybrid rice production, aiming to deepen our understanding of the innovation and optimization of hybrid rice breeding technologies.