Effect of IBA Concentration on The Growth of Ramin Cuttings (Gonystylus bancanus (Mig.) Kurz)

Ramin (Gonystylus bancanus (Miq) Kurz) is a peat swamp plant with commercial value in both national and international markets. However, the existence of ramin is threatened with extinction, due to the imbalance between regrowth and utilization, making it increasingly difficult to obtain ramin seedlings naturally. One of the efforts to propagate ramin is by cuttings. This study aimed to determine the optimum concentration of IBA (Indole Butyric Acid) growth regulator used in supporting the growth of ramin cuttings. The research method used a Randomized Group Design (RGD) consisting of 4 treatments and 6 replicates. The treatment consisted of P0 (control/0 ppm), P1 (IBA concentration 1000 ppm), and P3 (IBA concentration 1500 ppm). The data were analyzed descriptively qualitatively. The results showed that the provision of IBA affects the growth of ramin cuttings. Based on the percentage of cuttings that successfully grew, P0 successfully grew by 50%, P1 successfully grew by 83.33%, P2 successfully grew by 100% and P3 successfully grew by 100%. The average number of shoots of ramin cuttings that successfully grew in the treatment of P0 amounted to 0, P1 treatment amounted to 1, then P2 amounted to 2, and the highest number of shoots was in the treatment of P3 with 3 shoots. It can be concluded that the concentration of IBA 2000 ppm gives the best results when compared to other concentrations based on the percentage of cuttings that managed to grow and the average number of shoots.