Propagation of thornless Arkansas blackberries by hardwood cuttings

Effects of auxin application and cutting location on canes on adventitious root development in hardwood cuttings of three Arkansas thornless blackberry cultivars were studied. Dormant canes were collected from one-year-old plants of ‘Apache’, ‘Arapaho’, and ‘Navaho’ and stored in a cold room until February. Two- or three-node cuttings were taken from the canes at apical, mid, and basal locations along the cane and were placed under intermittent mist in a perlite-filled greenhouse bed. Cuttings were either untreated or treated with auxin indole-3-butyric acid (IBA), applied as a liquid quick dip at 0.3%. In general, cutting diameter was greatest for basal and smallest for apical cuttings. Significant interactions were observed for cultivar and cutting location and for cultivar and auxin treatment for rooting. ‘Apache’ with auxin treatment had the highest rooting percentage, and ‘Arapaho’ and ‘Navaho’ with auxin the lowest. For cuttings that rooted, auxin treatment increased the root rating, representing root system development, for ‘Apache’ and ‘Navaho’ but had no affect on ‘Arapaho’