The Effect of Plant Growth Regulators GA3 and Kinetin on the Growth of Honey Oranges (Citrus nobilis L.) from Siboras, Simalungun by In Vitro

Abstract

This study aims to determine the effect of the combination of GA3 and Kinetin in vitro on the seeds of Siam Madu orange (Citrus nobilis L.) from Siboras Simalungun. This study was conducted at the Biotechnology Laboratory of the Faculty of Agriculture, University of North Sumatra, Medan at an altitude of ± 25 meters above sea level from December 2024 to March 2025. This study used a Completely Randomized Design (CRD) method with 2 treatment factors and 3 replications. The first factor is the concentration of GA3 (G), namely G0 (0 ppm), G1 (2 ppm), and G2 (4 ppm). The second factor is the concentration of Kinetin (K), namely K0 (0 ppm), K1 (2 ppm), and K2 (3 ppm). The parameters observed in this study include the percentage of live explants, days to shoot emergence, number of shoots, shoot height, number of roots, root length, number of leaves, and stem diameter. The results showed that the administration of GA3 significantly affected the day of shoot emergence, shoot height, and number of roots, but did not significantly affect the number of shoots, root length, number of leaves, and stem diameter. The administration of Kinetin significantly affected the shoot height and root length, but did not significantly affect the day of shoot emergence, number of shoots, number of roots, number of leaves, and stem diameter, while the interaction between the combination of GA3 and Kinetin treatments significantly affected the day of shoot emergence, but did not significantly affect the number of shoots, shoot height, number of roots, root length, number of leaves, and stem diameter.