In vitro micropropagation of Arctostaphylos uva-ursi (L.) Sprengel.: Comparison between two methodologies

In vitro micropropagation of Arctostaphylos uva-ursi was performed to increase the number of ground cover species able to serve as substitute for members of the Rosaceae susceptible to fire blight. Explants (node segments) excised from plants growing in the greenhouse were established in vitro on a medium containing 10 M -naphthaleneacetic acid (NAA) and activated charcoal (2 g I^-1). Using in vitro grown shoots, two propagation procedures were used:- Culture of nodal fragments with 50 M NAA resulted in the growth of 6 to 7 nodes every 4 weeks, yielding 1 700 almost rootable shoots after 4 subcultures;- Development of axillary shoots obtained with media containing 25 M benzyladenine (BA) and 20 M indoleacetic acid (IAA) yielded almost 500 rootable shoots after 4 subcultures. The rate of propagation decreased after the 3^rd subculture.Percentage of in vitro rooted shoots reached 98% with diluted micronutrients and 10 M NAA but 31% of the plants died during acclimatization.Abbreviations BA benzyladenine - BM basal medium - HID high intensity discharge - IAA indoleacetic acid - IBA indolebutyric acid - NAA -naphthaleneacetic acid - PAR photosynthetic active radiation - 2iP 2-isopentenyladenine