Assesing genetic diversity of two tropical forest tree species (Scaphium macropodum and Fordia johorensis) in Jambi Province, Sumatra using isozyme markers

English. Genetic diversity of tropical forest tree species was assessed by using two tropical trees as model species namely Scaphium macropodum and Fordia johorensis in fragmented forest of Jambi Province, Sumatra. Leaf samples or inner bark tissues of the two species were collected from three sites viz. two sites are located in Silvagaina concession in Kuamang Kuning representing fragmented forest, and a site in an area of a private company PT. IFA-Barito Pacific Timber Group located in Pasir Mayang representing site linked with continuous forest. The analysis of six isozyme systems i.e. IDH, MDH, ME, PGD, PGI and SDH was conducted using potato starch gel electrophoresis. Estimates of genetic diversity i.e. mean number of alleles per locus, effective number of alleles per locus, percentage of polymorphic loci observed and expected heterozygosyties for F. johorensis is were not significantly different, while that for S. macropodum were significantly different (P 0.05) between Pasir Mayang and one of the sites in Kuamang Kuning. This suggest that fragmentation, under certain conditions, affected genetic diversity of S. macropodum

unknown. Telah diteliti keragaman genetik pohon hutan tropis menggunakan Scaphium macropodum dan Fordia johorensis sebagai model pada hutan yang terfragmentasi di Propinsi Jambi di Pulau Sumatra. Analisis dilakukan berdasarkan marka (penanda) isoenzim. Enam sistem enzim yang dianalisis yaitu IDH, MDH, ME, PGD, PGI dan SDH diperoleh dengan teknik gel elektroforesis pati kentang. Sampel daun atau kambium batang dari kedua jenis diperoleh dari tiga lokasi yaitu Camp Silvagama di Kuamang Kuning dan di areal milik satu perusahan swasta (PT. IFA Barito Pacific Timber Group) Pasir Mayang. Estimasi keragaman genetik yaitu rata-rata jumlah alel per lokus, jumlah efektif alel per lokus, persentase lokus polimorfik, heterozigositas yang diamati dan yang diharapkan, pada F. johorensis tidak berbeda nyata sedang pada S. macropodum sangat berbeda nyata (P0,05) antara Pasir Mayang dan salah satu lokasi di Kuamang Kuning. Dengan demikian, fragmentasi pada kondisi tertentu, mempengaruhi keragaman genetik S. macropodum