Comparative study on the effectiveness of cytokinin type and season on in vitro culture establishment ofArbutusspecies

Abstract

The aim of the present study was to assess the comparative dynamic of in vitro culture establishment of Arbutus species found in Greece i.e., Arbutus andrachne, Arbutus unedo and Arbutus × andrachnoides. The effectiveness of four different cytokinins i.e., benzyladenine (BA), zeatin (ZEA), 2-isopentenyl adenine (2iP) and kinetin (KIN) at a concentration of 2.5 mg L-1, in two different seasons, spring (May) and autumn (September) was examined. Solid Woody Plant Medium (WPM) was used and explants were excised from native adult plants. Almost all explants (90-100%) of all three species, in both seasons, produced shoots on the ZEA-medium. 2iP was effective too, in terms of shoot production and 88 or 95% of A. andrachne, 100 or 96% of A. × andrachnoides and 69 or 98% of A. unedo explants produced shoots in spring and autumn, respectively. BA proved less effective and KIN inappropriate for producing shoots in all three species and both seasons. The shoot number produced per explant was generally low being higher in the BA- and ZEA- medium (from 1.2 to 2.3). The use of ZEA led to greater shoot elongation (1.6-2.2 cm) in A. × andrachnoides and A. unedo. ZEA at 2.5 mg L-1 induced the highest shoot production in all three species and both seasons.