Application of Gibberellin Growth Regulatory Substance (GA3) and Modification of Planting Media on the Growth of Stem Tubers Porang (Amorphophalus muelleri Blume) Madiun Variety 1

The purpose of this study was to determine the effect of giving growth regulators GA3 and modification planting media on the growth of tuber stems of the porang plant Madiun variety 1. The growth parameters observed were: day of buda's emergence, the weight of porang tubers, diameter of porang tubers, plant height, stem diameter, leaf area and dry weight of porang plants. Data analysis of this study used two-way ANOVA analysis and continued with the Tukey. The results of this study showed that the treatment with ZPT GA3 60 ppm showed lower growth compared to the overall treatment. This is shown in all vegetative growth parameters: plant height (21.2 cm); stem diameter (0, 38 cm); leaf area (46.4 cm2) and dry weight (1.32 g). While the treatment without ZPT GA3 application showed better growth with the highest average value. This is shown in the plant height (31.56); the stem diameter (0.62 cm); leaf area (70.6 cm) and the dry weight (2.71 g). Meanwhile, the parameters of tuber weight and tuber diameter of plants tended to decrease with the highest reduction values experienced by C0P4 plants, which were 66.75 gr and 2.02 cm, respectively.