Effect of aromatic cytokinins and explant position on shoot multiplication of Asparagus offi cinalis L.

Asparagus offi cinalis has been widely studied, but little information is available about its in vitro response to exogenouscytokinin during shoot multiplication. To study the effects of different cytokinins on shoot multiplication of A. offi cinalis ‘Grolim’, in vitroculture was initiated from shoot segments cultured on media with Murashige and Skoog medium. Effects of different aromatic cytokinins(6-benzylaminopurine, 6-benzylaminopurine riboside and meta-topolin) applied in four concentrations (0.5, 1.0, 1.5, 2.0 mg/l) on shootmultiplication of ‘Grolim’ were tested. Effect of explant position (vertically or horizontally) on the shoot multiplication outcome was alsostudied. Both the length and the number of newly developed shoots were signifi cantly affected by explant position and cytokinin content ofthe medium. The highest numbers of shoots (4.9) were produced in the presence of 0.5 mg l-1 6-benzylaminopurine riboside when explantswere paced horizontally onto the medium. Although the longest shoots (41.5 mm) developed on explants placed vertically onto mediumsupplemented with 2.0 mg l-1 meta-topolin, the lengths of shoots developed on medium with 0.5 mg l-1 6-benzylaminopurine riboside werealso adequate in both explant position (29.5 and 33.6 mm placed horizontally and vertically, respectively)