ISHS Acta Horticulturae 131: In Vitro Culture, XXI IHC
FACTORS AFFECTING IN VITRO PROPAGATION OF APPLE CULTIVARS |
| Author: | R.H. Zimmerman |
| Abstract:
Five years research on factors affecting rooting of cuttings of 17 apple (Malus sylvestris Mill.) cultivars are summarized. Actively growing shoot tips were used to establish cultures that were proliferated using Murashige and Skoog revised medium. Cuttings taken from proliferating cultures were evaluated for rooting response to a number of different factors, although not all cultivars were evaluated for each factor. Indolebutyric acid was as effective as naphthaleneacetic acid in rooting 6 out of 7 cultivars. Optimum rooting was attained at a concentration range of 0.1 to 0.3 mg/l auxin; higher concentrations induced excess callus formation at the cutting bases and inhibited root and shoot growth. Phloroglucinol (PG) had no effect on the rooting of most of the 12 cultivars tested but enhanced rooting of 'Spartan' derived from certain explants and, to a lesser extent, of cuttings of 'Delicious' and 'Redspur Delicious'. It also reduced the amount of callus formed by the cuttings. Autoclaving did not alter the effectiveness of PG. Varying agar concentrations from 4.5 to 8.5 mg/l did not affect the rooting of two cultivars. Etiolation of the proliferating cultures, followed by several days regreening, improved the rooting of four cultivars. More than 2,000 tissue cultured trees have been grown in the nursery or field. An orchard with 675 trees of 17 cultivars has been growing for several years; some cultivars have flowered after one or two years in the field. | |
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