Variation in two Begonia × hiemalis clones after in vitro propagation

In order to study the variation of Begonia × hiemalis after in vitro propagation, one plant of ‘Aphrodite Pink’ and one of ‘Schwabenland Red’ were vegetatively propagated in four ways. One group of plants was obtained by propagation by means of cuttings. For the second group, the bacterial elimination system, as developed by Hakkaart and Versluijs (1983), was applied which includes an in vitro propagation step. The third and fourth groups were obtained by adding one and two cycles, respectively, of in vitro propagation after the bacterial elimination, so that one, two and three propagation cycles could be compared. One cycle, followed by bacterial elimination, gave nearly uniform offspring. However, when this was followed by one or two cycles of in vitro propagation, the variation increased. Variation also increased when the size of the plantlets obtained in vitro decreased. Thus, an important source of variation can be avoided by eliminating the smallest in vitro plantlets. It is recommended to flower and select the plants before propagation by conventional cuttings, whether or not a further in vitro propagation is applied after the bacterial elimination.