Effects of Indole-3-butyric Acid, Silver Nitrate, and Management on the Rooting and Stimulation of Active Growth of Hybrid Hazelnuts (Corylus americana x C. avellana) Stem Cuttings

Available breeding and genomic techniques, and further expansion of an eastern and midwestern U.S. hazelnut industry, have been restricted by challenges preventing the creation of asexual propagation protocol. Several studies of propagation by rooting of stem cuttings show some promise for research and mid-commercial scale genotype replication of the hazelnut (Corylus sp.); however, these results vary in their consistency within and across the hazelnut species. Recently, the successful rooting of european hazelnut (C. avellana) stem cuttings through the application of low levels of indole-3-butyric acid (IBA) and the ethylene inhibitors silver nitrate (AgNO₃) and 1-Methylcyclopropene (1-MCP) was reported. This study expands upon these findings to determine their effectiveness to induce rooting and allow for subsequent vegetative growth of hybrid hazelnuts (Corylus americana x C. avellana); Low concentrations of IBA were assessed independently and in combination with AgNO₃ to decipher if ethylene blockage treatments influence rooting, bud abscission, and/or bud break in cuttings of hybrid hazelnut stem tissue. Our results demonstrate high levels of hybrid hazelnut propagation are possible with low IBA concentration and that AgNO₃ helps to improve propagation through a high degree of bud break. However, AgNO₃ application did not significantly affect the number of successfully rooted cuttings or the reduction of bud abscission in the plant material studied, as was reported in previous work. Additionally, AgNO₃ application did not result in continued vegetative growth in all cases, whereas management practices, such as transplanting time, appear to be more effective in encouraging continuous growth.