Plant regeneration of red raspberry (Rubus idaeus) cultivars ‘Joan J’ and ‘Polana’

Abstract

Plants were regenerated from in vitro leaf and petiole tissues of Rubus spp. L. (red raspberry) ‘Joan J’ and ‘Polana’ in woody plant medium (WPM), with 200 mg L−1 polyvinylpyrrolidone (PVP), and various combinations of 6-benzylaminopurine (BA) and/or thidiazuron (TDZ). The effects of explant type and explant age on plant regeneration were also investigated. Results showed that the regeneration rates were 70% for ‘Joan J’ and 82.2% for ‘Polana,’ when 7-d-old leaf tissues were inoculated on WPM with 2.5 μM BA + 1.0 μM TDZ and WPM with 2.5 μM BA + 0.1 μM TDZ, respectively. For ‘Joan J,’ in vitro rooting was readily achieved (100%) in one-half Murashige and Skoog (MS) medium supplemented with 10 μM 1-naphthaleneacetic acid (NAA). For ‘Polana,’ a rooting rate of 75% was achieved when cuttings were pulsed in one-half MS with 20 μM NAA for 7 d and then transferred to auxin-free one-half MS medium. An efficient ex vitro rooting frequency (> 80%) was obtained for both cultivars when cuttings were quickly dipped in 500 μM Indole-3-burytic acid (IBA) or NAA, and inserted to Sunshine Mix no. 1 (Fisons Western Corp., Vancouver, Canada) for a 4-wk rooting and acclimatization period. Regenerated plants were eventually grown in the greenhouse. This research will assist germplasm improvement using biotechnology techniques for raspberries and other Rubus species.