Investigation on Effects of IBA Treatments and Ethylene Inhibitors on the Rooting and Bud Retention of Semi-hardwood Cuttings from ‘Tonda Gentile delle Langhe’ Hazelnut Cultivar.

The most common techniques of propagation of hazelnut are by stool layering and rooted suckers. Propagation by cutting can be considered an alternative, rapid and relatively economic method but the technique has not yet been transferred to an industrial scale due to poor rooting ability and cutting survival of most cultivars. The effect of IBA (indole-3-butyric acid) treatments at two concentrations (500 and 1000 mg/L) on the rooting and bud retention of semihardwood hazelnut cuttings from cultivar ‘Tonda Gentile delle Langhe’ was investigated in 2010 and 2011. In addition, the application of two ethylene inhibitors, 1-MCP (1-Methylcyclopropene) and AgNO3, combined with IBA 1000 treatment, and the use of two different substrates (perlite and vermiculite; perlite and loam) were tested. The plant material was collected in July and, following the treatments, was placed on a planting bench under mist. The results have shown that IBA treatments promote high percentages of rooting (75.6% for IBA 500 and 76.9% for IBA 1000, means 2010-2011). The use of low IBA concentration (500 mg/L) in ‘Tonda Gentile delle Langhe’ promoted a percentage of rooted cuttings with retained buds interesting for the commercial propagation. The use of 1-MCP and AgNO3 in combination with IBA 1000 improved yield of rooted cuttings with living buds without modifying the rooting response; this result indicates an effect of ethylene on bud dropping following IBA treatment. The perlite and loam substrate gave a lower percentage of rooting in comparison with the perlite and vermiculite one.