(126) Response of Six Begonia Species to Different Substrate EC
There is limited information on optimal substrate EC level for begonia species (noncultivated hybrids). The objective of this study was to evaluate the response of six species to different substrate EC in a greenhouse. Begonia albopicta, B. cucullata var. cucullata, B. echinosepala var. elongatifolia, B. holtonis, B. fuchsioides (red) and B. fuchsioides (pink) plants were propagated by stem cuttings, and transplanted into plastic pots using a soilless mix. Five concentrations (20, 80, 200, 400, and 600 mg·L-1 N) of 17–5–17 fertilizer were applied as irrigation water to derive the five substrate EC levels. This experiment was a factorial randomized complete-block design. Substrate EC was measured weekly using the PourThru method and averaged for each treatment of each species. Inflorescence number, the longest stem length, SPAD readings, leaf area, and dry weight of each plant were measured as growth parameters. There were significant responses to substrate EC level and species on begonia growth parameters. The highest growth parameters of B. albopicta and B. cucullata were obtained at EC 5.7 and 6.6 mS·cm-1, respectively. The maximum growth of B. echinosepala and B. holtonis was observed at 2.6 and 3.0 mS·cm-1, respectively. B. fuchsioides, grown at 1.2 mS·cm-1, had the best growth parameter values. As EC level increased, SPAD value for B. fuchsioides (pink) and B. holtonis also increased. The highest SPAD reading was observed at EC 3.7 mS·cm-1 for B. albopicta, EC 6.6 mS·cm-1 for B. cucullata, EC 2.6 mS·cm-1 for B. echinosepala, and EC 4.1 mS·cm-1 for B. fuchsioides (red). Plant mortality of several begonia species was observed when grown at EC value above 6.4 or below 4.4 mS·cm-1.