In this study, we developed a mutagenesis protocol specifically
designed for chrysanthemum cv. “Candid” in order to
introduce genetic variation. By subjecting chrysanthemum shoots to
different doses of physical and chemical mutagens, we successfully
generated a total of 24 mutants, each with unique genetic compositions.
We observed that the mortality rate was lowest when the shoots were
exposed to 10 Gy gamma irradiation and 1.00% EMS. To assess the diversity
and relatedness among the mutants, we employed RAPD and SSR markers.
The combination of these markers allowed us to construct a dendrogram
that effectively categorized the mutant population into distinct clusters
based on the specific mutagen treatments. Interestingly, the mutants
induced by 10 Gy gamma irradiation exhibited greater genetic diversity
in terms of flower colors. On the other hand, mutants created with
1.00% EMS displayed a higher level of variation and yielded more viable
mutants. To determine the optimal markers for studying genetic diversity,
we analyzed the polymorphic information content (PIC) of different
markers. Among the tested markers, OPA-07 (RAPD) and JH47 (SSR) showed
the highest PIC values, indicating their effectiveness in capturing
genetic variability within the mutant population. Conversely, the
PIC values of OPD-07 and JH20 demonstrated the lowest among the markers
tested. Our results revealed a percentage of polymorphism ranging
from 81.81% to 100% for RAPD markers and 66.66% to 100% for SSR markers.
These findings indicate that physical mutation induced by 10 Gy gamma
irradiation can be clearly distinguished from chemical mutation induced
by EMS at concentrations of 1% and 0.75% in chrysanthemum cv. “Candid.″
Overall, this study provides valuable insights into the genetic composition
of the generated mutants and highlights their potential for enhancing
chrysanthemum-breeding programs. The identified markers, particularly,
OPA-07 and JH47, can serve as valuable tools for future studies aimed
at exploring and exploiting the genetic diversity within the chrysanthemum
population.