ASHS 2015 Annual Conference

Adventitious root formation on single-node cuttings of dormant floricane blackberries could allow their use in an alternative production system in colder climates or during the off-season. Greenhouse grown blackberries during the off-season or selling to a consumer as an annual could increase blackberry availability to a local market. Single-node dormant floricane cuttings of ‘Siskiyou’ and ‘Triple Crown’ taken from long lateral canes on 12-year-old field-grown plants  and younger (< 2-year-old) potted plants that were held in a cooler on the North Dakota State University campus. Four indole-3-butyric acid (IBA) treatments (0.1% IBA talc, 0.3% IBA talc, 1000 ppm KIBA quick dip, and 3000 ppm KIBA quick dip) were applied to the cuttings and compared to a non-treated control. Half of the cuttings were placed in cell packs in a 50/50 peat and perlite media mixture and half were placed between moistened paper towels. All of the cuttings were placed in partially sealed plastic bags and were subjected to low light conditions of approximately 15 µmol·m^-2·s^-1 for eight hours a day. Cuttings were misted the first week to maintain moisture and data were collected on rooting after 14 days.  Most of the adventitious roots developed at the base of the bud of the single-node cuttings. There was an increase in the number of roots on ‘Siskiyou’ cuttings taken from older plants. Additionally, the rooting of ‘Siskiyou’ cuttings in the media was better than when cuttings were placed between moistened paper towels.  Cuttings taken from older plants of ‘Siskiyou’ placed in the media mixture were found to have significantly longer roots than any of the other cultivar-media-IBA treatment combinations. The root rating of cuttings taken from older plants was found to be significantly higher than the cuttings from younger plants, and ‘Siskiyou’ had a significantly higher root rating than ‘Triple Crown.’ The IBA treatment had no effect on rooting.   Studies with other blackberry cultivars for rooting potential and fruiting from containerized, miniature plants will be performed.