Influence of Acute and Fractionated X-Ray Doses on Shoot Production of in Vitro Derived Explants of Gerbera jamesonii H. Bolus

In vitro mutation induction experiments will become economically relevant only if the genetic variation can be highly increased by this procedure. For that purpose the utilization of as high X-ray doses as possible are considered an important prerequisite. It was the objective to investigate the effect of split versus acute X-ray doses on in vitro derived micro shoots of Gebera jamesonii used as references system for plant species that can be propagated in vitro by axillary shoots. Splitting of doses between 10 Gy and 50 Gy into 2 or 3 fractions separated by periods of 4th each for recovery led to considerably rising shoot production. The recovery from damage, represented by accumulating the number of shoots developed during 16 weeks at 4 subsequent dates pf cutoff post-treatment, by propagation profiles, and by calculation of the factor of recovery, resulted in the application of very high X-ray doses only usable by means of multiple dose fraction procedures.