Paddy Germplasm Conservation: Strategies, Molecular Tools and Future Perspectives for Global Food Security

Abstract

Rice (Oryza sativa L.) is the dietary staple of over 3.5 billion people and supplies approximately 20% of global caloric intake. The genetic diversity embedded within paddy germplasm constitutes an irreplaceable reservoir for crop improvement, resilience breeding and the development of climate-adaptive varieties. This review consolidates current knowledge on paddy germplasm conservation, encompassing ex situ, in situ and cryogenic strategies; the molecular characterization of diversity; and the application of genomic technologies for collection management. The International Rice Germplasm Collection (IRGC) maintained at the International Rice Research Institute (IRRI), Philippines, holds over 127,000 accessions representing 24 Oryza species, making it the world's largest rice gene bank. Complementary national collections - notably those of India (>79,000), China (>70,000), Japan (>16,000) and the United States (>19,000) - collectively safeguard over 500,000 distinct accessions globally. Molecular marker technologies, from simple sequence repeats (SSRs) to genome-wide SNP arrays used in the 3,000 Rice Genomes (3K RG) project, have revolutionized diversity assessment and core collection development. Emerging challenges include genetic erosion driven by the replacement of traditional varieties with high-yielding cultivars, climate change impacts on wild Oryza habitats and declining regeneration resources. Future priorities encompass pangenome development, integrated genomic databases, community seed banks and policy-aligned conservation frameworks under the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). This review synthesizes data from over 150 peer-reviewed publications to provide a comprehensive reference for researchers, plant breeders and policymakers. The review highlights the practical implications of germplasm conservation for sustainable crop improvement and climate resilience. It serves as a valuable resource for researchers, plant breeders and policymakers engaged in ensuring long-term food and nutritional security.