EXPERIMENTAL EVIDENCE PROVING THE MUTATIONAL ORIGIN OF CARNATION CULTIVARS OBTAINED FROM THE "LONDORGA" GENOTYPE

More than 35 new cultivars have been produced by petal colour mutation from the carnation variety known as "LONDORGA", characterized by its resistance to Fusarium. Applications have been filed in several different countries to obtain protection for these new cultivars through the granting of plant breeders' rights.

In order to confirm their common origin, 17 of these cultivars were collected by the INRA/GEVES Centre in Saint Laurent du Var (06-France) and submitted to 3 applications of gamma irradiation (20, 40, 60 Gy) in order to study their histogenetic structure. Studies on their petal pigments were carried out with HPL chromatography in order to compare, firstly, non-irradiated varieties with one another and secondly, irradiated plants with a tendency to revert to the Londorga's original morphological type.

The frequency of such reversions proved to be highly irregular and depended upon the variety concerned. Applications of 40 and 60 Gy produced the most effective results, although the 60 Gy dosage often proved lethal. Comparison of the chromatograms confirmed morphological observations regarding:

• the identity of rival cultivars of the same colouring, and
• reversion to the Londorga chemotype.