Propagation Treatment Effects on Rooting of 'Cynthiana' Grape Hardwood Cuttings

Because of its appeal in the wine industry, ‘Cynthiana’ vines have become more sought after by grape growers. However, ‘Cynthiana’ is difficult to propagate from cuttings, which is the most common propagation method used for Iowa-adapted grape cultivars. Treatments with plant growth regulators, such as indole-3-butyric acid (IBA), applied to the base of the cuttings, have shown some improvements in root initiation (Barickman et al., 2003; Enderton et al., 2002). Studies have shown that root development must precede bud break to successfully propagate a new vine (Avery, 1999). A technique to promote root development before the buds begin to grow has been warming of the propagation media. Previous research at Iowa State University has shown that bottom heat as a pre-treatment in cold storage was beneficial to initiate root development, but when transferred to the field, there was no significant difference in surviving rooted cuttings (Barickman et al., 2003; Enderton et al., 2002).