2010 Volume 9 Issue 3 Pages 263-271
The Okinawa Islands have many wild and locally cultivated citrus genetic resources belonging to the mandarin group. However, these have decreased in recent years. It is essential, therefore, to explore the northern part of Okinawa Island and collect and study these citrus germplasm to ensure the availability of these fruit for future utilization. As a result of our exploration, we collected 30 local citrus genetic resources including wild monoembryonic Citrus tachibana (Makino) Tanaka var. attenuata, wild Citrus depressa Hayata (Shiikuwasha), and introduced and cultivated varieties; each of these exhibited different phenotypes. We thus were able to study the phenotype details and fruit quality of these citrus germplasms. Since polymethoxyflavonoids (PMFs) have been previously studied as a functional component in Citrus, we analyzed of our all samples using HPLC. As a result, we categorized the samples into 3 groups according to their PMFs constituents: ‘Shiikuwasha’, ‘C. keraji hort. ex Tanaka (Kabuchii)’, and others, which included C. oto hort. ex. Yu Tanaka and C. nobilis Lour. The ‘Shiikuwasha’ and ‘Kabuchii’ groups contained high amounts of PMFs. C. tarogayo hort. ex Yu Tanaka was included in the ‘Kabuchii’ group. Citrus tachibana (Makino) Tanaka var. attenuata and C. depressa (var. Ishikunibu) were included in the ‘Shiikuwasha’ group because of their specific constituents, despite having lower amounts of total PMFs than other cultivars in the ‘Shiikuwasha’ group.
