Growing season and hydrogen peroxide effects on root induction and development in Olea europaea L. (cvs 'Frantoio' and 'Gentile di Larino') cuttings

Semi-hardwood cuttings of 'Frantoio' (high rooting ability) and 'Gentile di Larino' (low rooting ability) cultivars were obtained from 1-year-old olive shoots sampled in mid-August during the 2000 and 2001 growing season. Semi-hardwood cuttings were dipped in IBA 4000ppm and H2O2 (0%-control or 3.5% w/v) solutions before rooting in greenhouse equipped with an automatic mist system. At 57 and 88 days after the beginning of rooting treatments cuttings were scored for the presence of callus, roots and roots number. In both cultivars and years, the IBA 4000 + H2O2 treatment significantly modified rooting of cuttings at 57 days in comparison with IBA 4000 treatment. The positive effects of H2O2 on rooting were gradually smoothed after 88 days. At the end of the propagation cycle (88th days), cuttings treated with IBA 4000 + H2O2 had significantly higher root number in comparison with those treated with IBA 4000 alone. (C) 2003 Elsevier B.V. All rights reserved.