Improving rooting and survival of softwood peach cuttings

Abstract

With leafy peach ( Prunus persica (L.) Batch) cuttings under mist, the highest rooting percentage, the largest number of roots per rooted cutting and the highest survival rates of the rooted cuttings were obtained by treating the bases of the cuttings for 24 h with a solution of 50 mg l −1 indolyl butyric acid (IBA) + 500 mg l −1 2,3-dichloro-1,4 naphthoquinone (dichlone). However, in the absence of dichlone, an IBA concentration of only 25 mg l −1 was optimal for rooting. Weekly sprays with a mixture of benzyladenine (BA) and naphthaleneacetic acid (NAA) increased the percentage of rooted cuttings in the poorly rooting cultivar ‘15–39’. Treatments to decrease the severe leaf-drop which occurred during the hardening-off period, i.e. weekly sprays with BA + NAA or with an anti-transpirant (TAG), if started at the beginning of the hardening-off period, considerably improved the survival of the rooted cuttings and their cytokinin content. Even more efficient in this respect were weekly sprays with a mixture of benzyladenine and myo-inositol, apparently due to an enhancement in the BA transport to the root system. This explanation is supported by the very marked accumulation of cytokinins in the roots of cuttings which had been sprayed with a mixture of myo-inositol and benzyladenine compared to plants which had been sprayed with benzyladenine alone. On the other hand, application of BA to leaves resulted in the inhibition of the transport of apically applied MI to the bases of the cuttings. Better leaf retention was related to increased levels of sugars in the cuttings. In the newly formed root system of the cuttings, a high cytokinin content was related to a high sugar content.