Factors affecting the response of leafless winter cuttings of apple and plum to IBA applied in powder formulation

Abstract

SummaryRooting of apple and plum cuttings in response to IBA applied in powder formulation was influenced by factors operating at the interface of the powder and the cutting stem. Decreasing coverage by applying IBA in granular form decreased rooting compared to the response to powder treatment, and increasing the loading of powder by pre-wetting the base increased rooting. A 50% aqueous solution of acetone, ethanol or methylated spirit was more effective than water but less effective than dimethylsulphoxide as a pre-wetting agent, but in general this method failed to produce as high rooting responses as dipping directly into solutions of IBA in the same solvents. Powder formulations retained on the cutting base for longer than 18 h could increase rooting further. Application of IBA to the cut base of the stem was more effective than to the proximal epidermis when powder was preceded by an organic solvent, as is the case when cuttings are dipped directly into IBA solution. However, IBA in powder formulati...