The effects of collection date, IBA, plant gender, nutrient availability, and rooting volume on adventitious root and lateral shoot formation by Salix planifolia stem cuttings from the Ungava Bay area (Quebec, Canada)

Salix planifolia Pursh ssp. planifolia is a shrub species presenting some p otential for the restoration of disturbed sites in the Canadian Arctic and Subarctic. The performance of S. planifolia stem cuttings collected in the Kuujjuaq area, northern Quebec, was evaluated in relation to sampling perio d, plant gender, exogenous auxin and nutrient concentration, rooting durati on, watering frequency, and soil volume. Cuttings collected in August, duri ng the active growing season, did not perform as well as those collected in June, October, or February. The only performance variables influenced by p lant gender were root number and shoot biomass, for which female cuttings w ere superior to males. Surprisingly the application of indole-3-butyric aci d inhibited adventitious root and lateral shoot number and biomass, particu larly at the highest concentration (10 000 mg.L-1). Increased nutrient avai lability enhanced root, but not shoot, growth. The best performance was obs erved when cuttings were grown in a relatively large soil volume (200 mL), watered frequently (twice a day), and allowed a relatively long period to r oot (70 days).