In vitro plant regeneration from leaves and internode sections of sweet cherry cultivars (Prunus avium L.)

Regeneration of adventitious shoots from leaves and, for the first time, from internode sections were compared and optimized for five economically important sweet cherry cultivars, i.e. Schneiders, Sweetheart, Starking Hardy Giant, Kordia and Regina (Prunus avium L.). The influence of basal media, carbon source, combination and dosage of phytohormones, ethylene inhibitor such as silver thiosulfate and a 16 h:8 h light:dark photoperiod versus complete darkness were evaluated. Both, DKW/WPM (1:1) and Quoirin/Lepoivre (QL) basal media stimulated organogenesis more than QL/WPM (1:1), Chee and Pool (CP), Murashige Skoog (MS), Driver and Kuniyuki (DKW) or woody plant (WPM) media did. An induction phase in darkness resulted in lower or zero regeneration rates. The best regeneration efficiencies were generally obtained with thidiazuron in combination with indole-3-butyric-acid. The addition of silver thiosulfate resulted in a similar or reduced regeneration efficiency. Significant genotypic variability in adventitious bud formation was evident for both explant sources, leaf and internode section. Adventitious shoots were obtained from 11% of leaf explants and 50% of internode sections indicating that shoot regeneration from internodes was significantly more efficient than from leaves.