Mutagenic treatment of multicellular meristems from vegetatively propagated plants generally results in the formation of chimeric plants. Mutated sectors can be increased and stabilized through the cutting-back method. The objective of the present research was to study the influence of the application of this method in the M1V2 population, originated from six different axillary buds from the M1V1 chrysanthemum branches. For this purpose, rooted plants of the cultivar ‘Ingrid’ (dark pink) were irradiated with 20 Gy of gamma-rays and the prune was carried out 40 days after planting. Frequency and spectrum of flower color mutants were evaluated. No mutants were observed in the control population. In the M1V2 population, 22.1% of the total plants were mutants (white color, dark bronze, pale pink, yellow, wine, variegated and cream). Among them, 1.8% were periclinal chimeras (with only one different color from the original) and the others showed mutated sectors. No differences were observed in mutation frequency and size of mutated sector among six M1V2 populations. The wine colored mutant was selected, multiplied and evaluated in a yield trial. This mutant named ‘Magali’ was multiplied and was released as a new cultivar.
Dendranthema grandiflora; mutation; gamma-rays; axillary bud; chimera; prune