HIGH EFFICIENCY SHOOT MULTIPLICATION FROM IN VITRO CULTURED MERISTEMS OF ARONIA MELANOCARPA CV. NERO

Axillary shoot meristems of black chokeberry (Aronia melanocarpa) cv. 'Nero', with 1-2 leaf primordia, were aseptically isolated and cultured on solid Murashige and Skoog (MS) medium supplemented with N-6-benzyladenine (BA, 0.5 - 2.0 mg/l) and indole-3-butyric acid (IBA, 0.1 - 1.0 mg/l). Although the frequency of shoot formation from in vitro cultured meristems was over 70% in all the four treatments, primary shoot induction was most effectively promoted by MS medium supplemented with 2.0 mg/l BA and 0.5 mg/l IBA. In this combination all the excised meristems responded by developing vigorous shoots, with some slight callus formation. Following establishment, based on the results of several preliminary testing experiments, the primary shoots were further cultured on solid MS medium supplemented with 1.0 mg/l BA + 0.1 mg/l IBA for proper shoot multiplication. The number of shoots formed per initial shoot varied largely (from 2 to 31), with an average multiplication rate of 7.84, and their length was found to be strongly dependent on their number. Thus, the length (revealing the vigour) was higher for shoots formed in lower number per initial shoot, reaching up to 3.3 cm after four weeks of in vitro culture. Almost all the developed shoots were vigorous enough for further multiplication by subculturing them on fresh MS medium every four weeks. This protocol would be useful for large scale micropropagation of black chokeberry cultivars from meristem explants.