Submitted to: International Journal of Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 10, 1995
Publication Date: N/A
Interpretive Summary: Eight enzyme systems were used to fingerprint sixty-four accessions of Nephelium maintained at the USDA/ARS, National Clonal Germplasm Repository in Hilo, Hawaii. The five taxa showed high levels of polymorphism with these enzymes, and the collection encompassed a significant amount of diversity. The data also suggested that N. hypoleucum, a species collected din Thailand, is the closest relative of rambutan (N. lappaceum var. lappaceum). N. lappaceum var. pallens is more closely related to pulasan (N. ramboutan-ake) than to rambutan.
Sixty-four accessions involving five taxa (four species with two taxonomic varieties) of Nephelium were fingerprinted, classified, and evaluated for intraspecific genetic diversity using isozyme polymorphism. All five taxa were polymorphic for most of the ten putative loci encoding eight enzymes. The number of alleles per locus ranged from three for Gpi-1 1to nine for Gpi-2 with a total of fifty-eight alleles. Fifty-five accessions possessed unique fingerprints indicating a significant level of diversity in the collection. On the average, eighty-six percent of the loci were polymorphic and the expected and observed heterozygosities were 0.390 and 0.402, respectively. The cluster analysis of the isozyme data revealed five distinct clusters representing the five taxa included in the study. Isozyme data suggested that the N. hypoleucum is the closest relative of N. lappaceum var. lappaceum. Interestingly, the N. lappaceum var. pallens accessions exhibited closer association with N. ramboutan-ake than with its sibling taxon N. lappaceum var. lappaceum. The isozyme results dispute the taxonomic relationship among the taxa of Nephelium. However, further taxonomic and evolutionary inferences would require a much broader survey on a larger sampling basis.