VARIABILITY OF PELARGONIUM PELTATUM CULTIVAR IN LONG-TERM IN VITRO CULTURE OF DISEASE-FREE NUCLEUS STOCKS.

Shoot-forming clusters originating from apex explants of the Pelargonium peltatum cv. ‘Ville de Paris’ tend to degenerate to a non-organogenic, proliferating callus in the course of 9 subcultures.
For the maintenance of the regeneration rate, disease-free in vitro donor plants were established in order to obtain nodal segments as transplants for axillary and adventitious shoot formation.
A bacteriological screening with basal segments was used for the selection of non-infected plantlets.
Due to the great variability of the progenies, the origin of morphological aberrations was studied.
Under in vitro and greenhouse conditions, the following variations were identified: total and sectorial chlorophyll deficiency in stems and petioles, marginal and central variegation, leaf malformations, hair leaves, dwarf forms with or without chlorophyll deficiency, enlarged plants (giants). The individually different chimeral constitution of the stock plants and the somaclonal variability contributed to the genetical diversity of in vitro regenerated plants.
The altered characteristic proved to be of differing stability under the conditions of in vitro propagation.

International Symposium on Propagation of Ornamental Plants

G. Reuther

https://doi.org/10.17660/ActaHortic.1988.226.90