ROOTING RESPONSE OF SHOOT CUTTINGS FROM THREE PEACH GROWTH HABITS

Authors: Tworkoski, Thomas; Takeda, Fumiomi

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2007
Publication Date: 11/12/2007
Citation: Tworkoski, T., Takeda, F. 2007. Rooting response of shoot cuttings from three peach growth habits. Scientia Horticultureae. 115:98-100.

Interpretive Summary: Peach trees (Prunus persica (L.) Batch) are grown for commercial production as scion budded to a rootstock but trees can die due to graft incompatibility. Alternatively, peach trees can be produced by rooting stem cuttings to provide uniform and efficient trees. Rooting of peach cuttings has been difficult. The cause for rooting failure may be internal hormone concentrations. In previous work we found Pillar had higher auxin hormone concentration than Standard and Compact tree growth habits of peach. To test the hypothesis that differences in auxin concentrations could affect rooting ability, we treated shoot cuttings from each growth habit with four concentrations of a root-inducing chemical, indole butyric acid (IBA). The numbers of shoots that rooted increased 79, 56, and 13%, respectively, in cuttings from Pillar than Standard and Compact that were treated with 250 ppm IBA, over control cuttings (0 ppm IBA). Pillar trees consistently grew more roots with greater root length per cutting than the other growth habits. Within peach and possibly other fruit trees, the capacity of shoot cuttings to develop roots can vary by cultivar and successful root induction with applied plant growth regulators may depend, in part, on internal hormone levels. The results indicate that root-inducing chemicals, such as IBA, should be applied at concentrations to match internal hormones in order to optimize rooting of shoot cuttings.

Technical Abstract: Current year shoot cuttings were collected in October and August from three growth habits of peach (Compact, Pillar, and Standard), treated with one of four concentrations of indole butyric acid (0, 250, 1250, and 2500 mg L-1 IBA). Rooting response was measured after five weeks in the greenhouse. Little or no rooting occurred with cuttings from any growth habit that was collected in October or in August when treated with 0 and 2500 mg L-1 IBA. In August, the number of shoots that rooted were greater in cuttings from Pillar (79 and 45%) than Compact (13 and 3%) treated with 250 and 1250 mg L-1 IBA, respectively. Cuttings from Standard trees had intermediate rooting of 56 and 6% at 250 and 1250 mg L-1 IBA, respectively. Pillar trees consistently grew more roots with greater root length per cutting than the other growth habits. It is proposed that differences in rooting response may be associated with differences among the growth habits in endogenous auxin concentration that had been found in previous studies. Within peach and possibly other fruit trees, the capacity of shoot cuttings to develop adventitious roots can vary by cultivar and successful root induction with exogenous plant growth regulators may depend, in part, on endogenous hormone levels.