Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 30, 2010
Publication Date: April 30, 2011
Citation: Takeda, F., Tworkoski, T., Finn, C.E. 2011. Blackberry propagation by non-leafy floricane cuttings. HortTechnology. 21(2):236-239. Interpretive Summary: Tissue culture has been used to propagate blackberry cultivars to meet the demand to fill new production acreage. Although tissue culture can produce large plant numbers, it is expensive, requires a high capital investment for the advanced technology, and the process for generating field-ready tissue cultured transplants takes 9 to 12 months. The blackberry industry needs an alternative method for using plant parts that are pruned in winter and that is simple and low-cost for generating blackberry transplants. In this study, we evaluated a mass propagation system of using hardwood cuttings taken in winter and rooting them in a modified enclosed system that did not use misters. Over 90% of hardwood cuttings of ‘Siskiyou’ blackberry rooted and produced shoots in the enclosed system, but less than half of cuttings of ‘Triple Crown’ blackberry rooted. Neither removal of buds or cytokinin application improved rooting percentage. The enclosed system is a useful method for propagating ‘Siskiyou’ blackberry by hardwood cuttings, but propagating ‘Triple Crown’ by this method is questionable.
Technical Abstract: Propagation of 1- or 2-node hardwood cuttings from blackberry (Rubus sp.) floricanes can be an efficient and reliable source of rooted transplants but consistent rooting is needed. Floricanes were collected from 9-year-old ‘Triple Crown’ and ‘Siskiyou’ plants on 5 November 2009, 3 December 2009, and 21 January 2010. The response of 1- and 2-node cuttings with and without excised axillary buds to an application of cytokinin was compared to control cuttings with intact axillary buds and no cytokinin. Differences in root development were evident in the two cultivars tested. The cuttings of ‘Siskiyou’ and ‘Triple Crown’ callused on cut ends, but much of the adventitious roots developed from the base of the axillary buds. Shoots emerged from the bud in approximately 90% of ‘Siskiyou’ cuttings stuck in November, December, and January. Rooting occurred in more than 90% of cuttings stuck in November and December, but declined in cuttings stuck on 21 January. In ‘Siskiyou’, bud excision had no effect on shoot and root emergence, but cytokinin treatment suppressed rooting in November and January cuttings. In ‘Triple Crown’ cuttings, shoot emergence and rooting were poorer than in ‘Siskiyou’ blackberry. In ‘Triple Crown’ cuttings, partial excision of buds reduced shoot emergence only in January but had no effect on rooting at all 3 sticking dates. Cytokinin treatment improved shoot emergence in November and December, but reduced rooting in January. The enclosed system is a viable method for propagating ‘Siskiyou’ blackberry by hardwood cuttings, but propagating ‘Triple Crown’ with this method is questionable.