Propagation success of cuttings as influenced by stage of propagation, 1-MCP and ethylene exposure and storage: part 2 Pelargonium

The propagation success of cuttings can be influenced by the stage of development at which they are shipped and stored, storage duration and exposure to ethylene inhibitors and/or ethylene. The objective of this study was to determine the effect of the propagation stage and ethylene inhibitor 1-MCP on the sensitivity of Impatiens hawkeri 'Super Sonic White' and 'Super Sonic Red' to ethylene and simulated shipment. Nine combinations of the propagation stage (1 = unrooted; 2 = callused; 3 = rooted), 1-MCP treatment (0 or 700 nL L-1) followed by ethylene treatment (0 or 1 µL L-1), and storage duration (0 or 2 days) were administered. Impatiens cuttings that were stored after being propagated to Stage 3 had the most yellow/necrotic leaves, while overall, 'Super Sonic White' had more than 'Super Sonic Red'. In both cultivars, cuttings propagated until Stage 3, before any gas treatment or storage, took the most propagation days to reach Stage 3 and had the lowest root fresh and dry weights. Stage 1 cuttings stored for 2 days reached Stage 3 in fewer days than unstored cuttings, such that if the 2-day storage was counted towards propagation days, the difference between unstored and stored cuttings was negligible. Cuttings treated with ethylene, and stored for 2 days at Stage 2, reached Stage 3 in the least number of propagation days. Most postharvest parameters were not significantly affected by 1-MCP. Cuttings treated with 1-MCP prior to ethylene took slightly longer to root than cuttings just treated with ethylene, but differences were ≤0.6 days. In summary, root development continued on cuttings in storage indicated that short term storage may be beneficial.