Characterization of cassava (Manihot esculenta Crantz) resistant to drought stress as a result of selection using PEG 6000

Cassava is a source of carbohydrates that grows in tropical areas. The largest cassava producing province in Indonesia is Lampung, and Central Lampung Regency is the main cassava production center in Lampung Province. Plant responses in response to drought vary, such as plants wilting, stomata closing, and chlorophyll content decreasing. The drought stress inducer used in this research was polyethylene glycol. Drought-sensitive cassava will show reduced growth, while tolerant plants will obtain new genotypes that are resistant to drought stress conditions. The aim of this research was to determine the drought tolerant concentration of PEG 6000; distinguish between chlorophyll a, b, and total; and determine the differences in stomata density and stress tolerance index in cassava treated with PEG 6000 and the control. The PEG 6000 treatment consisted of 5 concentration levels, namely 0%, 10%, 20%, 30%, and 40% with each treatment repeated 5 times. The tolerable concentration of PEG 6000 is 40%. The higher the concentration of PEG 6000, the lower the chlorophyll a, b and total content. As the concentration of PEG 6000 increases, the stomata density increases. The stress tolerance index of cassava is categorized into medium tolerant at concentrations of 10% and 20%, and tolerant at concentrations of 30% and 40%.