Articles
CULTIVAR DEVELOPMENT OF ORNAMENTAL MEMBERS OF THE PROTEACEAE
As with all ornamentals, however, it is imperative that we continue the development of new lines and products to keep pace with the ever-changing market.
The most important features of any new cultivar are novelty, quality, yield and reliability.
Research is an essential tool in understanding the biology of the plant, and in using this information in product improvement.
These problems are discussed in terms of cultivar registration and evaluation, and illustrated using Banksia breeding as an example.
The Banksia selection program is currently focused on the cut flower species B. coccinea, B. menziesii, B. hookeriana and B. prionotes, and two superior cultivars have so far been identified. ‘Waite Orange’ is a high yielding orange banksia with a production time intermediate between that of B. prionotes and B. hookeriana. Using a combination of B. prionotes, ‘Waite Orange’ and B. hookeriana, orange banksias can be produced almost year round. ‘Waite Crimson’ is a high yielding, mid-season B. coccinea with dark red blooms.
Vegetative propagation techniques, via rooted cuttings, have been developed for both cultivars.
The program is also aimed at interspecific hybridisation within the genus, to combine characters of interest across species barriers and so produce novel cultivars.
Research conducted on the structure and morphology of the pollen presenter and pollen grains across the genus has shown that there is variability in the structure of both, but particularly in the pollen presenter.
There are four major types of pollen presenter, elongated and cylindrical, short and cylindrical, short and ovoid, and papillose.
The location of the stigmatic groove also varies between species, with most terminal and longitudinal, but some subterminal and/or transverse in orientation.
It is important to specifically target the stigmatic croove in interspecific pollinations, as the pollen-receptive cells lie within the groove.