Oil characteristics of genetically improved cajuput ( <i>Melaleuca cajuputi</i> subsp <i>. cajuputi</i> ): An assessment of a cajuput breeding program in Indonesia

Cajuput (Melaleuca cajuputi subsp. cajuputi) is an essential oil-producing tree with significant economic and medicinal value in Indonesia. While breeding program have aimed to improve oil yield and 1,8-cineole content, there is notable absence of research integrating genetic improvements with advanced analytical techniques to comprehensively evaluate oil quality and plantation site suitability. This study addresses this gap by assessing the chemical composition, purity, and physicochemical properties of cajuput oil derived from improved seeds, alongside evaluating plantation site suitability across diverse regions in Indonesia. The samples were collected from eight locations: Aceh Besar-Aceh, Pekanbaru-Riau, North Lampung-Lampung, Tanggamus-Lampung, Gunungkidul-Yogyakarta, Bojonegoro–East Java, Bima-West Nusa Tenggara (WNT), and Biak Numfor-Papua. Oil analysis was conducted using Gas Chromatography-Mass Spectrometry (GC-MS), molecular distillation, and physicochemical tests, while soil chemical properties were analyzed to assess site suitability. The results revealed 80 chemical compounds dominated by 1,8-cineole (48.49 - 69.32%), followed by caryophyllene and terpineol. Molecular distillation increased 1,8-cineole content by 9.8 to 27.7% and adjusted the refractive index to meet Indonesian National Standard (SNI). Nine out of 21 samples conformed to SNI standard for all parameters. Soil analysis indicated suboptimal conditions in all locations due to nutrient deficiencies, low pH, and poor soil texture. However cajuput trees demonstrated strong adaptability to marginal soils. This study highlights the feasibility of integrating genetic improvements with advanced analytical techniques for sustainable cajuput oil production across diverse environmental conditions in Indonesia. It provides a foundation for optimizing plantation strategies and enhancing oil quality to meet growing market demands.