Regional projections and sampling strategies for the global germplasm resources collection of Oryza rufipogon Griff.

Abstract

Oryza rufipogon Griff., the wild progenitor of cultivated rice, contains essential genetic resources for rice improvement and global food security. Preserving the integrity of its germplasm has therefore become a critical conservation priority. In this study, we applied GIS based spatial analysis and the MaxEnt model, integrating global occurrence data of O. rufipogon with 20 environmental variables to predict suitable habitats during the Last Interglacial (LIG, 130 to 115 ka before present [BP]), the Last Glacial Maximum (LGM, 26–19 ka BP), and the present. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), and spatial clustering was conducted based on the contributions of Journal Pre-proof environmental factors. The results identified three current core ecological zones: the tropical monsoon region of Southeast and East Asia; the tropical grassland–monsoon region of South Asia; and the tropical rainforest region spanning northern Australia, the Philippines, and Indonesia. During the LGM, colder and drier climates led to a more fragmented distribution, whereas the LIG showed a clearer expansion into broader tropical and subtropical zones. Priority regions for O. rufipogon germplasm collection were identified across Southeast, East, and South Asia, as well as northern Australia. This study proposes a targeted sampling strategy that incorporates elevation, soil properties, and water availability, providing a solid scientific basis for global O. rufipogon surveys and the conservation of high-quality germplasm resources.