BIOSISTEMATIKA PAMELO (Citrus maxima (Burm.) Merr.) DI INDONESIA BERDASARKAN KAJIAN MORFOLOGIS, FITOKIMIA, DAN MOLEKULAR

Pummelo (Citrus maxima (Burm.) Merr.) is native fruit of tropical South East Asia regions. There are a number of commercial pummelo cultivars intensively cultivated in various orchards in Indonesia. Based on the information found in many literature, pummelo is known as having high morphological diversity, especially in fruit characters. Nevertheless, so far there is no comprehensive publication documenting this diversity as well as the taxonomic treatment at infraspecific level. Systematics study reported here used both phenetic and phylogenetic approaches to disclose infraspecific variation, taxonomic affinitity, and clarification of taxonomic identity of pummelo at infraspecific level based on morphological, phytochemistry, and molecular analysis. The objectives of this study were to generate open classification system a infraspecific level for Indonesian pummel, and reveal morphological, phytochemical, and molecular markers as basis for the infraspecific classification. Materials used in this study were vegetative and reproductive organs of 107 individuals. Morphological data from leaves, flowers, fruits and seeds were obtained from observation and measurements either in the field or laboratory. Phenetic affinity based on morphology was conducted on 60 accessions using 21 characters. Meanwhile, phenetic affinity based on leaf essential oils was performed on 40 accessions using compounds� composition and concentration analyzed using gas chromatography � mass spectrometry. Morphological and essential oil data were subjected to cluster analysis and principal component analysis. The molecular approach was conducted using DNA sequence analysis of ITS1 on 70 accesions and (GA)n repeat motifs of microsatellites on 80 accessions. Phylogenetic relationships was examined using minimum evolution method. Result of cluster analysis on morphological data revealed two main clusters corresponding to the existence of two cultivar groups of pummelo. Six morphological characters from leaves and fruit were identified as the major distinguishing characters for these two clusters based on principal component analysis. Results of morphological analysis as used as a basis for constructing open classification in which 60 accessions of pummelo was divided into two cultivar groups, the �Gulung Cultivar Group� and �Pamelo Cultivar Group�. Combination of leaf and fruit characters was found to be morphological marker for the recognition of cultivar groups. Analysis on the GC-MS chromatograms of 40 pummelo accessions revealed infraspecific variation on leaf essential oil. The qualitative and quantitative infraspecific variation was used to differentiate accessions into three chemotypes. They were recignized as �nerol-loliolide-allo aromadendrene�, �alpha selinene�, and �alpha pinene-delta carene� chemotypes, respectively. Analysis on the ITS1 sequence showed a low infraspecific variation of 1.83%, and thus supported the role of ITS1 as molecular marker for differentiating species. Meanwhile, sequence analysis on microsatellite containing (GA)n dinucleotide repeat discloses high genotypic variation on pummelo. This high genotypic variation was reflected in phylogeny tree constructed by minimum evolution method which showed the existence of 9 clades