Water stress enhances geranium (Pelargonium) cuttings rooting quality

Abstract Pelargonium nurseries in Europe encounter rooting problems due to the low quality of the cuttings supplied during the winter. The problem may be due to the poor quality of the stock plants from which the cuttings are harvested. The main problem that growers have is the prolonged shipping period and its effect on the viability and rootability of the cuttings once they arrive in Europe. We tested the effect of water stressing the stock plants grown grown in random block design in a commercial nursery and checked the rootability of cuttings after storage and the susceptibility of cuttings to rot. We assumed that mild water stress could harden the stock plant and thus the cuttings, and they would survive the journey better. Mild water stress improved the rooting ability of some Pelargonium varieties after days of storage compared to unstressed plants. Cuttings from water-stressed stock plants showed less decay after prolonged storage than unstressed stock plants as measured by percent rotten cutting. Chlorophyll content increased significantly in cuttings from stressed stock plants. The yield and physical parameters of the cuttings from stressed and nonstressed stock plants did not change. Results indicate that applying water stress to stock plants improves the quality of Pelargonium cuttings.