Agriculture Reference
In-Depth Information
Fig. 12.4
Impatiens walle-
riana
hybrids ready for sale.
(Photo courtesy of A. Bettin)
as one type of flower may dominate for a period to the exclusion of other flowers.
Under temperate Australian conditions it may take a major event such as a bushfire
to clean out competing vegetation and stimulate the germination of the plants being
sought. For example, in Western Australia approximately half of the
Banksia
spe-
cies in the family
Proteaceae
are killed by fire (Collins et al.
2009
). Seed germina-
tion and seed dispersal are also stimulated by fire, while other species regenerate
quickly re-sprout from ligno tubers (i.e. new growth from old surviving buds) and
dominating recruitment.
Direct breeding
The second source of domestication is the direct breeding of
new plants using existing genetic diversity. This has been highly successful for
a number of plants especially producing new roses. De Vries and Dubois (
1997
)
show that the rose is the highest sold cut flower in the Netherlands with 499 ha
being grown under glass and in the open in 2010 (APIH/Union Fleurs
2011
), with
chrysanthemums (
Chrysanthemum
spp
.)
and lillies
(Lilium
spp.) and gerberas in
order of popularity. In the US pot plant industry the most produced indoor plants
are orchids (13.3 million pots), poinsettias (7.6 million pots) and floral roses
(5.6 million pots) and for annual bedding and garden plants, the
Impatiens
and New
Impatiens
-New Guinea hybrids (Fig.
12.4
), as well as pansies and violas, petu-
nias, begonias and marigolds were most popular (APIH/Union Fleurs
2011
). Other
flowers such as the camellia (
Camellia sasanqua
), carnations (
Dianthus
spp.),
gerbera, hydrangea (
Hydrangea macrophylla
) and rhododendron (
Rhododendron
spp.) are also popular and have undergone considerable breeding to produce new
