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Osteospermum
(Dimprphoteca) fruticosa white
natural species type
mother stock that has been cultured
from new growth tips before the
virus can take hold to produce
‘clean’ mother stock. Examples include African daises (Osteospermum
or Dimorphotheca), Arctotis and
Diascia hybrids.
As is to be expected, tissue cultured
plants aren’t cheap, so they’re usually used as mother stock for breeding or vegetative propagation.
Growing fern spores isn’t easy. So
tissue culture once again comes to
the fore as a great way of germinating fern spores, Unlike the seedbearing plants, the tissue cultured
plantlets are usually grown and sold
directly to end-users. If you have
leather leaf fern,
‘bergvaring’ (Blechnum spp) or tree
ferns in your garden, the chances
are good that they were originally
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uniform rapid tissue
production
Ostesospermum jucundum
natural species type
Yellow Ostesospermum:
inter-species cross?"
produced in a laboratory using tissue culture.
Genetic engineering
Despite the bad rap that ‘GMOs’ get
in the press, there are many reasons
why they could be either a very
good or a very bad idea. In terms of
indigenous ornamentals, some genetically engineered varieties may
be growing quite happily in your
garden without you knowing their
origins.
Plant breeding usually means that
only genes from closely related species can be combined, but with genetic engineering, it’s possible to
cross species that are less closely
related by inserting selected genes.
Although most plant breeders keep
quiet about their secrets, there is
evidence that some of the fancy
Osteospermum varieties, for exam-
Agapanthus contrast with white
Ice (less flowers, but more reliable).
ple, may have been achieved by
crossing annual and perennial species that would not ordinarily have
been inter-species fertile.
Polyploidy is another interesting
phenomenon. It sometimes occurs
in nature. Instead of having two
sets of genes (one from each parent) plants can have three, four, or
even more sets of genes. The result?
Bigger flowers, bigger leaves and a
generally ‘pumped up’ appearance.
We suspect that Tecoma ‘Rocky
Horror’ is a natural polyploid. We
got it through traditional plant
breeding, but the results were
astounding to say the least!
Polyploidy can be encouraged in the
lab using colchicine, and there is a
possibility that some of the more
striking, large-flowered Agapanthus
varieties may have been created
Agapanthus white ice