Agriculture Reference
In-Depth Information
pollinated by other red cabbages. This is done
by ensuring that no other
Brassica oleracea
pollen can dilute the red cabbage pollen. As
bees have a range of at least 2 km, fine mesh
is used to cover the flowering plants to
prevent cross-pollination from (for example)
a flowering Brussels sprout.
material. This is the story of the cultivar.
A cultivar is propagated without change,
therefore by asexual means.
The Granny Smith apple found in almost
every fruiterer is the fruit of a clone; that is,
the tree from which it was picked is genetically
identical to the first chance seedling that grew
and fruited in Mrs Thomas Smith's garden
outside Sydney in 1860. This is achieved by
grafting a piece of the original tree (scion)
onto a rootstock (see Figure 2.14).
Hybrid and genetically modified seeds do not
'come true' when saved. They have to be
sourced fresh each season from the
multinationals - a goldmine for these
companies, expensive and usually
unnecessary for us.
The Granny Smith apple in Figure 2.14 on
the left is made up of a rootstock
(1)
and a
piece of the original Granny Smith tree
(2)
,
the scion. The standard rose on the right is
made up of three different parts. The
rootstock that forms the roots and the trunk
(1)
, with two different roses grafted onto to it;
one pink
(2)
and one white
(3)
.
Asexualpropagation-cuttinggrownand
graftedplants
Asexual propagation is all about producing
clones of a particular plant, creating a
population of genetically identical plant
3
2
2
1
1
Figure 2.14
Two examples of grafted plants.
