Duku ‘Kumpeh’ is one of the potential local type cultivars of Duku Lansium parasiticum (Osbeck) K.C. Sahni & Bennet.), from specific area in the Jambi. For sustainable utilization of this local germplasm of tropical fruit, understanding of reproduction and genetic information of the plant is needed. The reproductive system of a plant species is a factor that directly determine the potential and success of conservation germplasm for the future. Until now, the breeding system about this plant still unclear although there were different opinions whether duku produce asexually (apomictic), sexual or both. Based on this fact, it is necessary to clarify this problem. A total of 60 seeds from three parental trees (20 seeds from Kumpeh and 22 seeds from Dusun Tuo and 18 seeds from Muaro Panco) were germinated in the greenhouse for obtaining DNA samples. DNA samples were extracted using CTAB method and amplified using Inter Simple Sequences Repeat (ISSR) primers. Four selected primers: (CCT)8 (HQ200181), (AAT)10 (HQ200186), (AAG)6 (HQ200182) and (AG)10 (DQ453906) were used to amplify all DNA samples and estimate the magnitude of genetic variability and out-crossing rate. Based on analysis of genetic variability and assessment of level out-crossing rate of three parental and sixty progenies from three populations proved that local cultivar ‘Kumpeh’ were facultative apomictic breeding system. The existing identical of all progenies in Kumpeh population with their parental were very important for sustainably utilization of this local type duku ‘Kumpeh’. The detection genetic variability (even with low level) at Dusun Tuo and Muaro Panco population were very useful and strategic for genetic conservation and genetic improvement of these germplasm.
