Effect of Natural Auxin in Aloe vera and Synthetics on the Growth Success Level of Syzygium aqueum Cuttings

Water apple (Syzygium aqueum) is a horticultural fruit commodity with high economic value and continues to be developed through vegetative propagation to obtain uniform and high-quality seedlings. However, the success of water apple propagation through cuttings is still influenced by differences in cultivars and plant responses to the application of growth regulators, especially auxins. Information regarding the interaction between water apple cultivars and auxin types on the initial growth of cuttings is still limited. This study aims to evaluate the effect of cultivars and auxin types on shoot growth and rooting of water apple cuttings to support vegetative propagation of water apple. The study was arranged using a factorial randomized block design (5 × 4). Factor I: rose apple cultivars (Citra, Dalhari, Kancing Merah, Black Kingkong, and Madu Deli), Factor II: auxin application (control (without auxin, 4000 ppm IBA, 4000 ppm NAA and 30% Aloe vera). Each treatment was replicated four times, resulting in 80 experimental units, with each experimental unit consisting of 10 plant cuttings. Observations were made at 4, 6, and 8 weeks after planting. The results showed that the Madu Deli cultivar produced a higher number of shoots, number of roots, wet and dry root weights, and plant weight compared to other cultivars. Auxin application increased root growth of water apple cuttings compared to those without auxin, especially in the parameters of root number, root length, and root weight. The treatment of IBA and NAA 4000 ppm gave the best results and was consistently higher than the 30% Aloe vera treatment and the control. Although Aloe vera was able to increase cutting growth compared to those without auxin, its effectiveness was still lower than synthetic auxin. This study is important as a scientific basis in selecting the right cultivar and type of auxin to increase the success of vegetative propagation of water apple, especially in the Madu Deli cultivar.