Abstract:
In general, mutated cells are difficult to monitor but mutations which result in a
change in genome number are an exception and genome number mutations can be
identified by chromosome counting. In the present study, chimeric materials were
used as explant source, and higher percentages of tetraploid shoots were induced
from explants with higher ratio of tetraploid cells to diploid cells; explants
possessing 26% tetraploid cells regenerated 10% tetraploid plants, explants
possessing 15% tetraploid cells regenerated 4% tetraploid plants, and explants
possessing 11% tetraploid cells regenerated 2% tetraploid plants. The reliability of
the tetraploid nature of the regenerated plants, directly from colchicine treated
culture and from chimeric materials was confirmed by regenerating buds again from
explants of these plants, and amongst the six plants tested, five were confirmed to
be true tetraploids that regenerated 100% tetraploid plants, and the rest one to be a
chimera which regenerated 93% tetraploid plants. Results of the experiments
indicate that in vitro culture method could provide a useful way to separate
chimeras into individuals with one of the component cell genome numbers, and by
this it could produce 100% pure tetraploids from chimera plants for further genetic
studies of Echinacea purpurea L and for direct agricultural application.
