Rambutan is an annual plant that takes a long time to bear fruit. In vitro seed propagation is needed as an alternative to providing superior planting material. The growth regulator used in this study was Benzyl Amino Purin (BAP) which is type of growth regulator of the cytokinin group that most often used in plant propagation in vitro. The aim of this study was to examine the effect of BAP on the growth of several varieties of rambutan in vitro. The method used was a factorial completely randomized design with 2 factors, the first factor was rambutan varieties (binjai, rapiah, and ace), and the second factor was BAP concentrations (0, 2, 4, and 6 ppm). There were 12 treatment combinations and 3 time replications. Variables observed (shoot emergence time, number of shoots, shoot length) was analyzed using analysis of variance followed by 5% Duncan’s Multiple Range Test and other data (leaf emergence time, number of leaves, root emergence time, number of roots, and root length) were analyzed descriptively. The results showed that the combination of 0 ppm BAP and binjai variety gave the best results on shoot length, number of leaves, and number of roots. The 0 ppm BAP treatment gave the best results on the number of shoots, shoot length, number of leaves, number of roots, and root length. Binjai variety treatment gave the best results on the time of shoot emergence, shoot length, time of leaf appearance, number of leaves, time of root appearance, and number of roots.
