Variation of Fertility and Its Impact on Seed Harvesting in Seed Production Area of Sandalwood in Indonesia

The Seed Production Area (SPA) of sandalwood (Santalum album L.) in East Nusa Tenggara is Indonesia's sole designated site for sandalwood seed production. It was established 32 years ago using trees from six provenances on Timor Island. The SPA supports regional economies and ecological protection by producing high-quality seeds for commercially valuable trees and species conservation. Despite annual seed collection, information on reproductive status, genetic diversity, and genetic drift is limited. This study assessed fertility variation, genetic diversity, and the impacts of genetic drift on sandalwood seed production. Fertility was assessed through flower and fruit production, while genetic diversity was calculated using fertility and genetic drift data. The results showed high fertility variation (2.98), high genetic diversity (0.97), and low co-ancestry (0.03). This study revealed that 14.04% of trees contributed over 50% of the reproductive output. The effective population size (19.15%) indicates that a small percentage of trees contribute highly to seed production. To avoid dominance by highly fertile trees, seed collection is limited and mixed equally. These results provide a scientific basis for strategic seed production and genetic resource management. Recommendations include selectively pruning the crowns of highly fertile trees, increasing the number of fertile trees, and stimulating less fertile individuals to increase seed production while maintaining genetic diversity in the SPA. ©2025 The authors.