Evaluation of Drought Tolerance in In Vitro potato (Solanum tuberosum L.) cv. Dayang Sumbi Plantlets Using Polyethylene Glycol (PEG) 6000

Potato (Solanum tuberosum L.) is an important food crop whose productivity tends to decline under drought stress conditions. Water deficit limits water uptake, reduces cell turgor pressure, and disrupts photosynthesis, resulting in inhibited plant growth. Development of drought-tolerant potato cultivars can be achieved through in vitro culture using polyethylene glycol (PEG) 6000 as a selective agent that lowers the water potential of the culture medium without causing direct damage to plant cells. This study aimed to evaluate the effect of PEG 6000 on the growth of in vitro potato plantlets of the Dayang Sumbi cultivar and to determine the concentration that could still be tolerated under drought stress conditions. The experiment was conducted at the Botany Laboratory, Faculty of Mathematics and Natural Sciences, Universitas Lampung, using a Completely Randomized Design (CRD) with five PEG 6000 concentrations (0%, 5%, 10%, 15%, and 20%) and five replications. The observed parameters included plantlet survival percentage, plantlet height, number of leaves, and stomatal index. The data were analyzed using analysis of variance (ANOVA) followed by Tukey's Honestly Significant Difference (HSD) test at a 5% significance level. The results showed that all plantlets remained viable, with a 100% survival rate across all PEG 6000 concentrations during the two-week observation period. Significant differences were observed in plantlet height, leaf number, and stomatal index, all of which decreased progressively with increasing PEG 6000 concentration and reached their lowest values at 20% PEG 6000. A PEG 6000 concentration of 10% was found to support the growth tolerance of Solanum tuberosum L. cv. Dayang Sumbi plantlets under in vitro drought stress conditions.